Patent Publication Number: US-9418022-B2

Title: Storage system in which information is prevented

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-166253, filed Jul. 26, 2012; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a secure storage system for example. 
     BACKGROUND 
     Generally, in a field requiring information security, there is employed an authentication technique using mutually shared confidential information and encoding as means for certifying transmission and reception of confidential information and self validity. 
     An application range of the authentication technique is very wide, and when this technique is applied to a storage device, this technique is used for protecting user&#39;s data and protecting a copyright of contents in some cases. As application examples for protecting a copyright of contents, there are known certification of validity of an SD card (registered trademark) as secure storage and CPRM (Content Protection for Recordable Media) for playing back, recording and managing secret information for protecting contents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically showing a storage system to which an embodiment is applied; 
         FIG. 2  is a diagram showing an example of a case where contents are recorded from a host device into secure storage; 
         FIG. 3  is a diagram showing an example of a case where contents in the secure storage are read from the host device; 
         FIG. 4  is a diagram showing an example of a configuration in which the host device, the secure storage and extended storage are combined; 
         FIG. 5  is a diagram showing an example of connection between the secure storage and the extended storage; 
         FIG. 6  is a diagram showing another example of the connection between the secure storage and the extended storage; 
         FIGS. 7A, 7B and 7C  are diagrams showing examples of combination of the secure storage and the extended storage; 
         FIG. 8  is a diagram showing an example of a using method of the secure storage and the extended storage; 
         FIG. 9  is a diagram showing an example of data structures in the secure storage and the extended storage; 
         FIG. 10  is a diagram showing another example of the data structures in the secure storage and the extended storage; 
         FIG. 11  is a diagram showing another example of the data structures in the secure storage and the extended storage; 
         FIG. 12  is a diagram showing an example of a using method using the secure storage and the extended storage; 
         FIG. 13  is a diagram showing another example of the using method using the secure storage and the extended storage; 
         FIG. 14  is a diagram showing an example of authentication processing of the host device and the secure storage according to a first embodiment; 
         FIG. 15  is a diagram showing an example of status check processing of the host device and the secure storage according to the first embodiment; 
         FIG. 16  is a diagram showing an example of initialization processing according to the first embodiment; 
         FIG. 17  is a diagram showing an example of processing of the host device for checking a state of the secure storage; 
         FIG. 18  is a diagram showing an example of a method for preventing a plurality of host devices from simultaneously playing back contents according to the first embodiment; 
         FIG. 19  is a diagram showing an example of a case where the secure storage and the extended storage are used in combination; 
         FIG. 20  is a diagram showing a first example of identifiers according to a second embodiment; 
         FIG. 21  is a diagram showing a second example of the identifiers according to the second embodiment; 
         FIGS. 22A and 22B  are diagrams showing an example of link information stored in the secure storage; 
         FIGS. 23A and 23B  are diagrams showing an example of link information stored in the extended storage; 
         FIG. 24  is a diagram showing an example of an editing operation of contents; 
         FIG. 25  is a diagram showing an example of data structures of the secure storage and the extended storage according to a third embodiment; 
         FIG. 26  is a diagram showing an example of a control method of contents according to the third embodiment; 
         FIG. 27  is a diagram showing a first control method of movement of contents according to the third embodiment; 
         FIG. 28  is a diagram showing a second control method of movement of contents according to the third embodiment; 
         FIG. 29  is a diagram showing a synchronization method of the secure storage and the extended storage according to the third embodiment; 
         FIG. 30  is a diagram showing an example of data structures of the secure storage and the extended storage; 
         FIG. 31  is a diagram showing another example of the data structures of the secure storage and the extended storage; 
         FIG. 32  is a diagram showing another example of the data structures of the secure storage and the extended storage; 
         FIG. 33  is a diagram showing a specific example of a controller ID stored in a controller according to a fourth embodiment; 
         FIG. 34  is a diagram showing a specific example of the controller ID stored in a controller according to the fourth embodiment; 
         FIG. 35  is a diagram showing operation procedure when an authentication key exchange based on elliptic curve encoding is used; 
         FIG. 36  is a diagram showing an example of a configuration of a memory system according to a fifth embodiment; 
         FIG. 37  is a diagram showing an authentication operation of the memory system according to the fifth embodiment; 
         FIG. 38  diagram showing key management information according to the fifth embodiment; 
         FIG. 39  is a diagram showing an example of a configuration of a memory system when an MKB technique is applied; 
         FIG. 40  is a diagram showing a case where information is written when a NAND flash memory is manufactured; 
         FIG. 41  is a flowchart of the case where information is written when the NAND flash memory is manufactured; 
         FIG. 42  is a diagram showing a case where a card vendor writes the key management information; 
         FIG. 43  is a flowchart showing the case where the card vendor writes the key the management information; 
         FIG. 44  is a diagram showing an example of a storage medium in which the key management information is not stored; 
         FIG. 45  is a diagram showing a case where the key management information is downloaded to and stored in the storage medium; and 
         FIG. 46  is a diagram showing a case where an encoded FKeyID batch is downloaded and stored. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, a storage system includes a host device, a secure storing medium, and a non-secure storing medium. The secure storing medium includes: a memory provided with a protected first storing region which stores secret information sent from the host device, and a second storing region which stores encoded contents; and a controller which carries out authentication processing for accessing the first storing region. The host device and the secure storing medium produce a bus key which is shared only by the host device and the secure storing medium by authentication processing, and which is used for encoding processing when information of the first storing region is sent and received between the host device and the secure storing medium. The host device has the capability to request the secure storing medium to send a status. The secure storing medium produces a message authentication code based on the bus key in reply to the sending request of the status, and the host device verifies validity of the message authentication code based on the bus key. 
     Embodiments will be described with reference to the drawings. In the embodiments, the same members are designated with the same symbols. 
     Configurations of a host device and secure storage, as well as an authentication method will be described using  FIGS. 1 to 3 . 
       FIG. 1  schematically shows a storage system to which the embodiment is applied, and shows the configurations of the host device  11  and the secure storage  12 . 
     As the secure storage  12 , a memory card such as a SD card and a hard disk (HDD, hereinafter) can be applied. The secure storage  12  includes a memory  13  and a controller  14  for controlling the memory  13 . Examples of the memory  13  are a NAND flash memory and the HDD. A function required for the controller  14  varies in accordance with types of memories. 
     The memory  13  and the controller  14  are manufactured by the same vendor or by independent vendors depending upon a case. 
     The memory  13  is classified into a memory peripheral circuit  13   a  and a data holding region  13   b  as a storing section. The data holding region  13   b  is classified into a playback-dedicated region  13   c  and a record/playback region  13   d.    
     Later-described contents such as image are stored in the playback-dedicated region  13   c  for example. 
     The record/playback region  13   d  includes a system region  13   e  in which system information is stored, a protection region  13   f  in which secure data such as content key is stored, and a normal region  13   g  in which data such as encoded contents are stored. 
     The memory peripheral circuit  13   a  carries out access control of data with respect to the data holding region  13   b , and memory interface control corresponding to memory interface between the controller  14  and the memory  13 . 
     When the memory  13  is a HAND flash memory, the interface is a NAND interface, and when the memory  13  is a HDD, the interface is a SATA interface. 
     The controller  14  includes a memory control circuit  14   a , an authentication circuit  14   b  and a ROM Area  14   c . The memory control circuit  14   a  controls the memory  13  through a memory interface  15 . 
     Here, the memory control circuit  14   a  also carries out host interface control which corresponds to an interface between the host device  11  and the controller  14 . 
     The memory authentication circuit  14   b  carries out processing concerning authentication between the secure storage  12  and the host device  11 . 
     The host interface  16  is a SD interface when the secure storage  12  is a SD card, and is a USB or network interface when the secure storage  12  is a HDD. 
     The host device  11  is a television receiver or a personal computer for example, but the host device  11  is not limited to them. 
     The host device  11  includes a storage control function  17  for controlling the secure storage  12  through a host interface  16 . The host device  11  reads data, records data and carries out authentication between the host device  11  and the secure storage  12  through this function. 
     The host device  11  includes a host authentication function  18  which carries out authentication between the host device  11  and the memory authentication circuit  14   b , a content encoding/decoding function  19  for encoding/decoding contents, a content control unit  20  for controlling playback and recording operations of contents, and a content playback unit  21  for playing contents back. 
     Next, an example of the authentication method between the host device  11  and the secure storage  12  will be described using  FIGS. 2 and 3 . 
       FIG. 2  shows an example of a case where contents are recorded in the secure storage  12  from the host device  11 . 
     The host device  11  includes a pair of a host device key and a host device certification. The secure storage  12  includes a medium device key and a medium device certification in a system region of the memory  13 . 
     Here, the device keys and the device certifications have structures based on public key encoding. More specifically, a device public key corresponding to the device key is included in the device certification, and devices which authenticate exchange the device public keys with each other to authenticate. These public keys are exchanged by an authentication processor  11 A of the host device  11  and an authentication processor  12 A of the secure storage  12 . An authentication step between the authentication processors will be described later. 
     The device certification includes a device ID and an electronic signature for certifying validity of a certification. If the authentication is established, the host device  11  can access the protection region  13   f  in the secure storage  12 . 
     Secret information prepared by a secret information preparing unit  11 B of the host device  11 , e.g., a content key used for encoding of contents is recorded in the protection region  13   f  of the memory  13 . 
     Secret information is used for an encoding/decoding (encrypting/decrypting) operation of contents, encoded contents encoded by an encoder/decoder (encryptor/decrypter)  11 C are recorded in the normal region  13   g  in the secure storage  12 . The content control unit  20  controls all of processing of the authentication processor  11 A, processing of the encoder/decoder  11 C which encodes contents, and processing of the secret information preparing unit  11 B. 
     The secure storage  12  may include a controller ID (IDcntr) as controller unique information which is attendant on the controller  14 . The controller ID may be supplied to the host device  11  through the authentication processor  12 A. 
     The secure storage  12  may include a memory ID (IDmemory) as memory unique information recorded in a playback-dedicated region  13   c  of the memory  13  or the like. The memory ID may be supplied to the host device  11  through the authentication processor  12 A or without through the authentication processor  12 A. 
     The secure storage  12  includes all of or some of a controller ID, a memory ID and a device ID, or combination information thereof as information capable of identifying individual secure storage. 
     (Secure Storage and Extended Storage) 
       FIG. 3  shows an example of a case where contents in the secure storage are read from the host device. Like the method described with reference to  FIG. 2 , if the authentication is established, the host device  11  can access the protection region  13   f  in the secure storage  12 . 
     The host device  11  reads secret information recorded in the protection region  13   f . Further, the host device  11  reads encoded contents recorded in the normal region  13   g . The secret information and the encoded contents are processed by the encoder/decoder  11 C and decoded contents are obtained. The content control unit  20  controls all of the authentication processing, and content decoding processing. 
       FIG. 4  shows a configuration in which the host device  11 , the secure storage  12  and extended storage  30  are combined. 
     The host device  11  and the secure storage  12  have the same configurations as those shown in  FIG. 1 . The extended storage  30  has a configuration similar to that of the secure storage  12 , but the extended storage  30  is non-secure storage which does not include the memory authentication circuit and the protection region. 
     The secure storage  12  and the extended storage  30  are connected to the host device  11 . 
     This configuration is based on an assumption that the secure storage  12  is a SD card and the extended storage is a HDD. 
     Generally, a storage capacity of the SD card is as small as 1/10 to 1/100 of the HDD. When video contents are recorded in a SD card as the secure storage  12 , the number of recordable contents is limited due to constraints of the storage capacity. Hence, if the HDD is connected to the host device  11  as the extended storage  30  and a record/playback region in the extended storage  30  is combined with a record/playback region of the SD card and used, the recording region of contents can largely be increased. 
     It is also possible to select a HDD as the secure storage  12  of course. In this case, although the constraints of the storage capacity are moderated, a form size is increased. In recent years, a utilizing scene of video contents is increased, and it becomes general not only to watch TV but also to watch video contents on a smartphone and a mobile terminal such as a tablet terminal. A storage having small form size is suitable for watching on a mobile terminal. Hence, a HDD having a large form size as compared with a SD card is not suitable for the mobile terminal. 
     Based on such a background, the embodiment proposes to satisfy both the storage capacity and the form size by combining the secure storage  11  and the extended storage  30 . 
     (First Connecting Method Between Secure Storage And Extended Storage) 
       FIG. 5  shows a first connecting method between the secure storage  12  and the extended storage  30 . In this example, the host device  11  is a television set for example, the secure storage  12  is a SD card for example, and the extended storage  30  is a HDD (USB-HDD) which can be connected through USB for example. In the following description, the host device  11  is also called a television set  11 , the secure storage  12  is also called a SD card  12 , and the extended storage  30  is also called an USB-HDD  30 . 
     The television set  11  includes a SD card slot through which the television set  11  is connected to the SD card  12 , and also includes a USB connection terminal through which the USB-HDD  30  is connected to the television set  11  as a USB device. The SD card  12  and the USB-HDD  30  are connected to the television set  11  using these connection interfaces. 
     In this example, secret information such as a key is recorded in the SD card  12 , and encoded contents are recorded in the USB-HDD  30 . By combining these information sets, the television set  11  can playback the contents. 
       FIG. 5  shows that encoded contents are recorded in the USB-HDD  30 , but the embodiment is not limited to this, and the encoded contents may be recorded in the SD card  12 . The number of encoded contents is not limited to one and may be two or more. 
     (Second Connection Method Between Secure Storage and Extended Storage) 
       FIG. 6  shows a second connection method between the secure storage  12  and the extended storage  30 . In this example, the USB-HDD  30  as the extended storage includes a SD card slot through which the SD card  12  as the secure storage is connected to the USB-HDD  30 . The television set  11  as the host device includes a USB connection terminal through which the USB-HDD  30  is connected to the television set  11 . 
     The SD card  12  is connected to the USB-HDD  30  and the USB-HDD  30  is connected to the television set  11  using these connection interfaces. Secret information such as a key is recorded in the SD card  12 , and encoded contents are recorded in the USB-HDD  30 . The television set  11  can playback contents by combining these information sets. 
     The USB-HDD  30  includes a function for accessing the protection region and the normal region in the SD card  12 . More specifically, the USB-HDD  30  includes a bridge controller (not shown) for converting the SD interface into a USB interface. 
     (Combination of Secure Storage and Extended Storage) 
     The secure storage  12  and the extended storage  30  can be combined variously. 
       FIGS. 7A, 7B and 7C  show combining methods of the secure storage and the extended storage. 
       FIG. 7A  shows an example in which one secure storage  12  and one extended storage  30  are combined. 
       FIG. 7B  shows an example in which one secure storage and two extended storage  30 - 1  and  30 - 2  are combined. In this case, the one secure storage is commonly possessed by the two extended storage  30 - 1  and  30 - 2 . 
       FIG. 7C  shows an example in which three secure storage  12 - 1 ,  12 - 2  and  12 - 3  and one extended storage  30  are combined. In this case, the one extended storage  30  is commonly possessed by the three secure storage  12 - 1 ,  12 - 2 , and  12 - 3 . 
       FIG. 8  shows a using example of the secure storage  12  and the extended storage  30 . In the case of the shown in  FIG. 8 , contents and secret information are downloaded to the television set  11  as the host device  11  from a content server (not shown). In this example, secret information  1  corresponds to contents  1 , and secret information  2  corresponds to contents  2 . Any of the secret information sets are recorded in the SD card as the secure storage  12  through the television set  11 . The contents  1  and the contents  2  are recorded in the USB-HDD  30 . The contents  1  are recorded in the SD card  12 . 
     After the contents and the secret information sets are recorded in the SD card and the USB-HDD, the television set  11  decodes contents in the SD card  12  or the USB-HDD  30  using the secret information in the SD card  12  and plays back the contents. This can be carried out at home. 
     The SD card  12  of high portability can be taken out from home and can be inserted into a tablet terminal  40 . The tablet terminal  40  combines the secret information  2  and the contents  2  recorded in the SD card  12 , decodes the contents  1  in the SD card  12 , and plays back the contents  1 . 
       FIG. 8  shows the example in which information or content is downloaded from the content server. However, the embodiment is not limited to this, and the embodiment can also be applied to a case where contents are sent from a broadcasting device to the television set  11  for example. In this case, the host device  11  such as the television set usually produces the secret information. 
     (Internal Data Configuration of Secure Storage and Extended Storage) 
       FIG. 9  is a diagram showing an example of a data structure in the secure storage and the extended storage. 
     The data configuration in a combination of the secure storage  12  and the extended storage  30  shown in  FIG. 4  will be described. The configuration shown in  FIG. 9  corresponds to the shown in  FIG. 7A . 
     As described above, there are the protection region  13   f  and the normal region  13   g  in the secure storage  12 , and there is a normal region  30   a  in the extended storage  30 . The combination of the secure storage  12  and the extended storage  30  is called a virtual secure storage. 
     As described above, secret information is recorded in the protection region  13   f  in the secure storage  12 , and encoded contents are recorded in the normal region  13   g . Memory interface which is attendant on the encoded contents is also recorded in the normal region  13   g.    
     Link information indicative of a relation between the secure storage  12  and the extended storage  30  is recorded in the protection region  13   f  of the secure storage  12 . Here, the link information may be recorded in the normal region  13   g  instead of in the protection region  13   f . That is, when it is necessary to protect the link information itself, it is recorded in the protection region  13   f , and when it is unnecessary to protect the link information, it is recorded in the normal region  13   g.    
     As described above, encoded contents are recorded in the normal region  30   a  in the extended storage  30 , and link information is also recorded in the normal region  30   a . Here, link information recorded in the secure storage  12  and link information recorded in the extended storage  30  may be of the same format or different format. At least information designating the extended storage  30  is included in link information recorded in the secure storage  12 , and at least information designating the secure storage  12  is included in link information recorded in the extended storage  30 . A configuration of link information will be described later. 
       FIG. 10  shows data configuration in another combination of a secure storage and extended storage. The configuration shown in  FIG. 10  corresponds to the shown in  FIG. 7B . 
     That is, a virtual secure storage includes one secure storage  12  and a plurality of extended storage  30 - 1 ,  30 - 2  and  30 - 3 . Information designating the extended storage  30 - 1 ,  30 - 2  and  30 - 3  is included in link information in the secure storage  12 , and information designating the secure storage  12  is included in link information in each of the extended storage  30 - 1 ,  30 - 2  and  30 - 3 . The secure storage  12  and the extended storage  30 - 1 ,  30 - 2  and  30 - 3  are associated with each other by the link information. 
       FIG. 11  shows a data configuration of another combination of secure storage and an extended storage. The configuration shown in  FIG. 11  corresponds to the shown in  FIG. 7C . That is, virtual secure storages  12 - 1 ,  12 - 2  and  12 - 3  include a plurality of secure storage and one extended storage  30 . Information designating the extended storage  30  is included in link information in each of the secure storage  12 - 1 ,  12 - 2  and  12 - 3 , and information designating the secure storage  12 - 1 ,  12 - 2  and  12 - 3  is included in link information in the extended storage  30 . The secure storage  12 - 1 ,  12 - 2  and  12 - 3  and the extended storage  30  are associated with each other by the link information. 
     The basic configurations of the host device  11  and the secure storage  12 , the authentication method, and the combining methods of the secure storage  12  and the extended storage  30  have been described above. 
     To realize the authentication method, and the combining method of the secure storage  12  and the extended storage  30 , there are several problems which must be solved. 
       FIG. 12  shows one example of the using method using a secure storage and extended storage, and is a diagram for explaining a first problem. 
     As described above, secret information which is required for playing back contents such as a key is recorded in the protection region  13   f  of the secure storage  12 . To read secret information recorded in the protection region  13   f  and to record the secret information, authentication is required. Hence, secret information is prevented from being read, being written or being copied in an unauthorized manner. However, encoded contents themselves are recorded in the normal region  13   g . Hence, it is possible to easily read, write and copy the encoded contents. 
     When the host device  11  plays back contents, secret information in the secure storage  12  is necessary irrespective of a place where encoded contents are recorded and irrespective of a copy status. However, data size of the secret information is generally much smaller than that of encoded contents. 
     Hence, as shown in  FIG. 12 , a secure storage  12  and an extended storage  30 - 1  are connected to a host device  11 - 1  for example, and when contents are to be played back, the host device  11  first reads secret information from the secure storage  12 . Then, encoded contents in the extended storage  30 - 1  are sequentially read to playback the contents. 
     Normally, if secret information is once acquired, the host device  11  caches it in an internal memory in a playback process of encoded contents. That is, when secret information is cached in the host device  11 , it is possible to continue the playback operation even if the secure storage  12  is pulled out from the host device  11 - 1 . In this state, the secure storage  12  is inserted into a host device  11 - 2 . 
     Another extended storage  30 - 2  is connected to the host device  11 - 2 , and similar encoded contents are recorded in the extended storage  30 - 2 . In this case, the host device  11 - 2  reads secret information from a connected secure storage, reads encoded contents from similarly connected another extended storage, and the host device  11 - 2  can playback the contents. 
     As described above, the host device  11 - 1  continues the playback operation. In this state, although copy of the secret information is prevented, the secret information can be played back from a plurality of locations at the same time, and it looks as if the contents are copied. Of course, since the secret information itself is not copied, a secure storage is required for playing back the contents, and the contents are prevented from being simultaneously and freely copied and played back on a large scale, but there is a possibility that such an operation manner is forbidden depending upon an entitled person of contents. 
       FIG. 13  shows another example of the using method using a secure storage and an extended storage, and is a diagram for explaining a second problem. 
     In  FIG. 13 , a host device  11 - 1  and a host device  11 - 2  are connected to a transmission unit  50  at the same time. The transmission unit  50  carries out IP transmission on a local network for example. 
     The transmission unit  50  is connected to a secure storage  12  and an extended storage  30 , and the host device  11 - 1  and the host device  11 - 2  can access the protection region  13   f  and the normal region  13   g  of the secure storage  12  and the normal region of the extended storage  30  through the transmission unit  50 . 
     In the state shown in  FIG. 13 , although the number of secret information sets connected to the protection region  13   f  of the secure storage  12  is one, the secret information can be accessed from the plurality of host devices  11 - 1  and  11 - 2  at the same time. Hence, the host devices  11 - 1  and  11 - 2  can playback contents recorded in the extended storage  30 . 
     In this example also, like the first problem, there is a possibility that such an operation manner is forbidden depending upon a person entitled of contents. Especially, this operation manner can be carried out even when secret information and encoded contents are recorded in the secure storage  12  no matter whether the extended storage  30  exists. 
     First Embodiment 
       FIGS. 14 to 18  show a first embodiment, and this embodiment is for solving the first and second problems. 
       FIG. 14  is a state diagram of authentication.  FIG. 14  shows a possible state of a host device  11  and secure storage  12 . 
     First, there is an initial state (S 11 ) as a state where authentication between the host device  11  and the secure storage  12  is not completed. In this state, the host device  11  cannot access the protection region  13   f  in the secure storage  12 . 
     Next, there is an authentication-completed state (S 12 ) where authentication between the host device  11  and the secure storage  12  is completed. In this state, the host device  11  can access the protection region  13   f  in the secure storage  12 . 
     In addition to these states, an intermediate state 1 (S 13 ) and an intermediate state 2 (S 14 ) may exist during process in which the initial state S 11  is shifted to the authentication-completed state S 12 . 
     Arrows shown in  FIG. 14  show directions in which a state can be shifted to another state. Each of these states is commonly possessed by one host device  11  and one secure storage  12 , and the secure storage  12  cannot possess the plurality of host devices  11  and the authentication-completed state at the same time. 
       FIG. 15  shows an example of authentication processing according to the first embodiment. 
     As described above, the host device  11  and the secure storage  12  respectively include device keys and device certifications. The host device  11  sends the host device certification and a host random number 1 (Hr) to the secure storage  12  (S 21 ). 
     The secure storage  12  produces a medium random number 1 (Mr) and a medium random number 2 (Mn), and calculates a parameter P from the medium random number 2 (S 22 ). 
     The secure storage  12  gives a signature calculated by the medium device key to these messages together with the medium device certification, the medium random number 1, the parameter P and the host random number 1, and sends them to the host device  11  (S 23 ). 
     The host device  11  produces a host random number 2 (Hn), and calculates a parameter Q from the host random number 2. A bus key (BK) is calculated from the host random number 2 and the parameter P (S 24 ). 
     The host device  11  gives a signature calculated by the host device key to the parameter Q and a medium random number (Mr) and these messages, and send them to the secure storage  12  (S 25 ). 
     The secure storage  12  calculates the bus key BK using the parameter Q and the host random number 2 (S 26 ). 
     When the above processing is completed without any delay, this means that a common bus key is established between the host device  11  and the secure storage  12 , and this state is called a session established or an authentication-completed state. 
     Here, the bus key is commonly possessed, in a confidential fashion, by the secure storage  12  and a host device  11  of an interested party who carries out the authentication processing, and a person other than this secure storage  12  and this host device  11  of the interested party cannot know the bus key. The bus key is used for encoding processing when information of the protection region  13   f  is sent or received between the host device  11  and the secure storage  12 . That is, a person other than the host device  11  as the interested party and the secure storage  12  cannot acquire or falsify the information of a transmission path between the host device  11  and the secure storage  12 . 
     A signature given from a distributor of the certification is put on the device certification, and when the certification is received, the validity of the signature is checked. Further, a certification identification number or a device identification number is included in the device certification. 
     This authentication step is based on a known method, various modifications can be conceived from differences in authentication types, and the present application can be applied to any of the methods. 
     According to the first embodiment, when the authentication processing is carried out by the host device  11  and the secure storage  12 , a common bus key is produced only for the host device  11  and the secure storage  12  which carry out the authentication processing. Hence, even if a secure storage  12  having this bus key is connected to another host device at the same time, since this other host device does not have a bus key which is in common with the secure storage  12 , it is not possible to access the protection region  13   f  in the secure storage  12 . 
     (Initialization Processing) 
       FIG. 16  shows one example of initialization processing according to the first embodiment. When a host device  11  carries out authentication with a secure storage  12 , if the secure storage  12  is in an authentication-completed state with another host device (S 31 ), it is necessary to first bring a state of the secure storage  12  back to the initial state and then, authentication processing is carried out. 
     Hence, in this case, the host device  11  first issues an initializing request to the secure storage  12  (S 32 ). 
     In accordance with the initializing request, the secure storage  12  shift a state of itself from the authentication-completed state to the initial state (S 33 ). The shifting operation to the initial state corresponds to abandonment of a produced bus key. 
     When the shifting operation to the initial state is completed, the secure storage  12  sends a response to indicate that the initialization is normally completed (S 34 ). 
     Concerning this initializing request, the host device  11  may output the initializing request irrespective of a state of the secure storage  12 . In this case, even if the secure storage  12  is in the initial state, the secure storage  12  receives this request, an internal state is left as the initial state as it is, and sends, to the host device, information that the secure storage  12  is in the initial state. 
     (Status Check) 
       FIG. 17  shows a status check step of the first embodiment in which the host device  11  checks a state (status) of the secure storage  12 . 
     Here, the host device  11  may be already in the authentication-completed state between the host device  11  and the secure storage  12 , or may be in a stage before the host device  11  carries out authentication and the secure storage  12  is already in the authentication-completed state with another host device (S 41 ). 
     Hence, the host device  11  sends, to the secure storage  12 , a request to confirm the authentication state and nonce information (S 42 ). Here, the term “nonce” is very much like a random number which is produced by host device  11  every time. 
     In accordance with the received request, the secure storage  12  gives a message authentication code (MAC) produced using a bus key to an authentication state of the secure storage  12  itself, an authenticated host certification number and received nonce information (S 43 ), and sends them to the host device  11  (S 44 ). 
     If the secure storage  12  is in the initial state, production of the message authentication code may be omitted. Further, the host certification number may be omitted. 
     The host device  11  verifies validity of the message authentication code of information received from the secure storage  12  based on the bus key, and if the validity is verified, it is determined that the received message is proper, and an authentication state of the secure storage  12  is obtained (S 45 ). 
     According to the first embodiment, the secure storage  12  produces the message authentication code based on the bus key, and the host device  11  verifies the validity of the message authentication code. Therefore, it is possible to avoid a case where an authentication state is falsified by a third person having no bus key. 
     Further, the host device  11  requests the secure storage  12  to send nonce information, and the secure storage  12  produces a message authentication code in a state where nonce information is included. Therefore, it is possible to prevent a third person having no bus key from pretending to be an authenticated party. 
       FIG. 18  shows a method of solving the second problem according to the first embodiment. This method can also be used for solving the first problem. 
     This method is based on assumption that a plurality of host devices  11 - 1  and  11 - 2  can access the secure storage  12  and the extended storage  30  through the transmission unit  50  as described above. 
     Here, the host device  11 - 1  is in the authentication-completed state with the secure storage  12 . That is, since the host device  11 - 1  can access the protection region of the secure storage  12 , the host device  11 - 1  can obtain secret information and can playback encoded contents. 
     The host device  11  checks a status of the secure storage  12  periodically during playback of contents. As a result of the status check, if the secure storage  12  is shifted to a non-authentication-completed state, or although the authentication is completed, if the secure storage  12  is in the authentication-completed state with another host device, the host device  11 - 1  performs control, e.g., stops the playback for example. 
     According to this method, the host device  11 - 1  can playback contents only when the host device  11 - 1  can possess the authentication state of the secure storage  12 . Hence, it is possible to avoid the problem that a plurality of host devices can playback contents at the same time. 
     It is also possible to solve the first problem by this method. For example, in a state where the secure storage  12  is connected to the host device  11 - 1 , if the host device  11 - 1  periodically checks the status of the secure storage  12  and the secure storage  12  is pulled out from the host device  11 - 1  during playback of contents and the secure storage  12  is connected to another host device  11 - 2 , the host device  11 - 1  cannot obtain a proper result of status check. Hence, the host device  11 - 1  can finish the playback of contents. 
     Effects and expansion of the using method of the first embodiment will also be described. In recent years, with the development of an IP network, an infrastructure of accessing contents recorded in a home server located at home from outside to playback the contents is being set up. When the contents are commercial contents having a copyright, there is a possibility that simultaneous access from a plurality of locations causes a serious problem. Especially since data size of secret information recorded in a protection region is small, an unspecified number people can playback the contents in principle. 
     As means for preventing this, an encoded type for exchanging information in a safe manner between two devices which are generally called link protection is applied. Typical examples of the link protection are DTCP-IP (Digital Transmission Content Protection) and DRM (Digital Rights Management). 
     These link protections require re-encoding of contents in some cases. The re-encoding of contents is a method of once decoding the encoding in a recording state by a device, and contents are re-encoded by a bus key produced by the link protection technique and the re-encoded contents are sent. In this case, a sending-side device must carry out the decoding operation and the encoding operation at the same time, and a mounting load is large. 
     According to the method of the embodiment, on the other hand, since it is unnecessary to re-encoding contents, it is easy to mount the device, and it is possible to prevent an unspecified number persons from playing back contents at the same time. 
     When this method is applied, the following method can additionally be applied. 
     It is described above that it is possible to access the protection region  13   f  existing in the secure storage  12  if the host device  11  and the secure storage  12  completes the authentication. Here, an interior of the protection region  13   f  may be divided into a plurality of protection regions. 
     Each of the divided protection regions of the protection region  13   f  may be allocated as a region for recording secret information of contents supplied from an entitled person of the content. Here, when it is required to possess the authentication state by the status check depending upon an entitled person of contents or when it is not required to possess the authentication state depending upon an entitled person of contents, a problem whether the status check should be applied may be determined in each of the divided protection regions in the protection region  13   f . For example, in the case of downloaded contents, an entitled person of the downloaded contents does not require to possess the authentication state. Hence, when accessing a protection region where secret information of content distributed by the entitled person of contents is recorded, it is possible to select an operation manner that it is unnecessary to confirm that the authentication state should be possessed. 
     In the case of broadcasted videotaped content, an entitled person of the broadcasted videotaped content requires to possess the authentication state. Hence, when accessing a protection region where secret information of contents distributed by the entitled person of the contents, it is possible to select an operation manner that it is necessary to confirm that the authentication state is possessed. 
     By confirming the possession of the authentication state in accordance with request of an entitled person of contents, there is the following merit for example. Generally, when video contents are delivered from a network server, it takes time to download the contents. On the other hand, a user desires to playback the video contents without waiting for completion of the download. In the download, it is necessary to carry out the authentication between the server and the secure storage  12 , and to record secret information. 
     In playback, it is necessary to carry out the authentication processing between a playback unit and the secure storage  12 , and to read secret information. That is, contents are played back while downloading the contents, it is necessary that two different persons carry out the authentication processing with respect to the same secure storage  12 . Here, when an entitled person of contents who delivers the video contents does not require possession of the authentication state, it is possible to continue the playback even if the two different persons appropriately carry out the authentication processing with respect to the same secure storage  12 . 
     In the broadcasted videotaped content also, it is desired to playback contents while recording the contents in some cases, i.e., it is desired to record and read secret information at the same time in some cases, like competing-program playback or chasing playback. In this case, however, a picture recorder and a playback unit are usually the same device. That is, when recording and reading operations of secret information, the same host device certification can be utilized. In other words, in a recording processor and a playback processor in the same device, since it is possible to share the possessed authentication state, it is unnecessary to again carry out the authentication processing whenever secret information is recorded or read. 
     Second Embodiment 
       FIG. 19  shows an example of a case where secure storage and extended storage are used in combination. 
     As described above, one secure storage and one extended storage are combined in some cases, a plurality of extended storage is combined with one secure storage in some cases, or a plurality of secure storage is combined with one extended storage in some cases. 
     As shown in  FIG. 19 , a plurality of extended storage  30 - 1  to  30 - 4  is combined with a plurality of secure storage  12 - 1  to  12 - 4  in some cases. In this case, the host device needs to know which secure storage and which extended storage are combined and used. Hence, it is necessary to obtain an identifier to identify each of the secure storage and extended storage. 
       FIGS. 20 to 23  show the second embodiment, and shows means for identifying which secure storage and which extended storage are combined and used. 
       FIG. 20  shows a first example of the identifier. In  FIG. 20 , a controller ID is stored in a controller  14  in a secure storage  12 , and a memory ID is stored in a playback-dedicated region of a memory  13 . A device ID is given to a medium device certification held in a system region of a memory  13  in some cases. A host device  11  can uniquely identify individual secure storage  12  by any one of them or a combination thereof. 
     The extended storage  30  is provided with a number which can identify the individual elements in many cases. In an ATA (AT Attachment) interface which is widely used as an interface of a HDD for example, a command called an identify device exists as a command for obtaining an attribute of individual ATA devices. If the identify device is issued, the ATA device sends device information to the host device  11  as a response to the command. An example of the device information is information which can identify individual elements such as a model number, a serial number and world wide name (WWN). The information can be used so that the host device  11  uniquely identifies an extended storage  30 . 
       FIG. 21  shows a second example of the identifier. In  FIG. 21 , the secure storage  12  is the same as that shown in the first example shown in  FIG. 20 . In the extended storage  30 , if an individual identifiable number is not included in the extended storage  30  when the extended storage  30  is shipped, the host device  11  can give the individual identifiable number. 
     In this case, the host device  11  has an identifier producing function formed from firmware for example, and produces an extended storage ID by the identifier producing function. This produced extended storage ID is supplied to the extended storage  30 , and is recorded in the normal region as an identification number of the extended storage  30 . 
     According to such a configuration, an identifier can be given to an extended storage having no individual identifiable number, and based on this identifier, the host device  11  can identify the extended storage. 
     Next, a using method of an identifier obtained from  FIG. 20 or 21 , or a combination thereof will be described. 
     As described with reference to  FIGS. 9 to 11 , the data structure includes link information indicative of a relation between the secure storage  12  and the extended storage  30 . The link information is recorded in both the secure storage and extended storage. 
       FIGS. 22A and 22B  show link information recorded in the secure storage  12 . An identifier of the extended storage obtained by  FIG. 20 or 21  is included in link information in the secure storage  12 . 
     Here, for a case where one secure storage  12  is combined with a plurality of extended storage  30  and used, link information is formed from a plurality of extended storage information #0 to #N−1 as show in  FIG. 22A . 
     As show in  FIG. 22B , an identifier of an extended storage is included in extended storage information. More specifically, for example, a serial number, a model number and a world wide name shown in  FIG. 20  are included. 
     When these identifiers are not set, an extended storage ID given by the host device  11  shown in  FIG. 21  can be used as extended storage information. 
     The extended storage information may include both an identifier which is set in the extended storage and an extended storage ID given by the host device  11 . 
     The extended storage information may include information which designates a file directory in the secure storage  12  associated with the extended storage  30 . This will be described later. 
       FIGS. 23A and 23B  show one example of link information which is recorded in the extended storage  30 . 
       FIG. 23A  is similar to  FIG. 22A . As shown in  FIG. 23B , an identifier (Media ID) of the secure storage  12  is included in link information in the extended storage. That is, the identifier (Media ID) of the secure storage  12  is included in each extended storage information. 
     In this example, a medium ID is included as a secure storage identifier which is obtained by one of a controller ID, a memory ID and a device certification, or a combination thereof. Information which is associated with the secure storage  12  and which designates a file directory in the extended storage  30  may also be included. This will be described later. 
     According to the second embodiment, the extended storage  30  and the secure storage  12  include link information which associate each of secure storage and each of extended storage, and this link information includes an identifier which is set for the secure storage  12  and the extended storage  30 . Hence, even when a plurality of secure storage and a plurality of extended storage are combined and used, it is possible to uniquely identify each of the secure storage and each of the extended storage by referring to the link information. 
     Third Embodiment 
     As described above, secret information corresponding to each of contents is recorded in the protection region in the secure storage  12 , and encoded contents are recorded in one or both of the normal region in the secure storage  12  and the normal region in the extended storage  30 . 
     Generally, video contents are not only played back, and changing processing of substance of encoded contents such as editing processing including division of video contents and deleting processing of video contents are also carried out. 
     As shown in  FIG. 24 , when the same encoded contents exist in both the secure storage  12  and the extended storage  30  and only the secure storage  12  is taken out and connected to the tablet terminal  40  and operation such as edition and deletion is carried out with respect to the contents in the tablet terminal  40 , a mismatch is generated between the contents in the secure storage  12  and the contents in the extended storage  30 . 
     There exists a case where video contents are played back and a user watches motion picture of one hour for example, and the video contents are halfway played back for 30 minutes and playback is once stopped and then, rest is played back. This is generally called resume playback, and information of timing when playback is stopped is stored in a non-volatile memory in the host device  11  as mark information. Alternatively, similar mark information is recorded in the secure storage  12  or the extended storage  30 . 
     When playback is carried out, host device  11  selects one of the mark information sets based on which the playback of rest content is carried out. At this time, there is a case where the mark information exists in both the secure storage  12  and the extended storage  30 , only the secure storage  12  is connected to the host device  11  and playback is continued and in this state, the playback is stopped. In such a case, there is a possibility that a mismatch is generated between the mark information in the secure storage  12  and the mark information in the extended storage  30  and the host device  11  becomes confused about which mark information should be used. 
     When only the secure storage  12  is taken out to access contents and then the secure storage  12  and the extended storage  30  are connected to each other to access the contents, it becomes difficult to handle the information. 
     Hence, in such a using state of the secure storage  12  and the extended storage  30 , the third embodiment makes it possible to reliably carry out processing without causing confusion of a user concerning a using method, and without causing a problem of compatibility when the secure storage  12  and the extended storage  30  are used by a plurality of host devices  11  which are manufactured by different vendors. 
     The third embodiment will be described using  FIGS. 25 to 32 . 
       FIG. 25  shows a data structure in the secure storage  12  and the extended storage  30 . As described above, the system region, the protection region, the playback-dedicated region and the normal region exist in the secure storage  12  but here, the normal region will be described. 
     As shown in  FIG. 25 , a normal region  13   g  in the secure storage  12  is classified into a stand-alone region (SAD) and an extended region (EXDS). The stand-alone region (SAD) is a region where contents, secret information, control information and the like are stored, and contents in the stand-alone region (SAD) can be played back and substance thereof can be changed by the secure storage  12  alone as will be described later. An extended region (EXDS) can be used in information which is used in combination with contents saved in an extended region (EXDN) or can be used only in the extended region (EXDN), and information which is used by providing a using rule is stored in the extended region (EXDS) as will be described later. 
     A normal region  30   a  in the extended storage  30  is the extended region (EXDN). 
     Here, the following rule is applied to the stand-alone region (SAD) and the extended region (EXDS).
         The same content must not be stored in the stand-alone region (SAD) and the extended region (EXDS) redundantly.   When contents are moved from the stand-alone region (SAD) to the extended region (EXDS), the contents must be moved to the extended region (EXDS) and the contents in the stand-alone region (SAD) must be deleted.   When contents are moved from the extended region (EXDS) to the stand-alone region (SAD), the contents must be moved to the stand-alone region (SAD) and the contents in the extended region (EXDS) must be deleted.   The same contents may be recorded in the extended region (EXDS) of the secure storage  12  and the extended region (EXDN) in the extended storage  30 .   Different contents having the same file name must not be recorded in the extended region (EXDS) of the secure storage  12  and the extended region (EXDN) in the extended storage  30 .   Secret information has a relation with contents in the stand-alone region (SAD), contents in the extended region (EXDS) and contents in the extended region (EXDN).   Content management information of contents recorded in the stand-alone region (SAD) of the secure storage  12  must be recorded in the stand-alone region (SAD) of the secure storage  12 .   Content management information of contents recorded in the extended region (EXDS) of the secure storage  12  or the extended region (EXDN) of the extended storage  30  must be recorded in the extended region (EXDS) of the secure storage  12 .       

     Further, the following constraints may be added depending on circumstances.
         A group of contents recorded in the extended region (EXDS) of the secure storage  12  must be a subset of a group of contents recorded in the extended storage  30 .       

     (Control of Movement of Contents) 
       FIG. 26  shows a control method of contents when both the secure storage  12  and the extended storage  30  are connected to the host device  11 . More specifically,  FIG. 26  shows the control method of contents in the stand-alone region (SAD) and the extended region (EXDS) of the secure storage  12 . Here, the following terms will be defined.
         Playback: to playback contents   Record: to record contents   Edit: To edit contents. Edit includes division of contents, deletion of a portion of contents, and connection portions of contents.   Move: To move contents and secret information to another secure storage, or to move contents and secret information to another device or storage which is protected by another DRM (Digital Rights Management)   Transfer: To transfer contents between stand-alone region (SAD) and extended region (EXDS)       

     In  FIG. 26 , the initial state is as follows:
         Contents A and contents C are recorded in the stand-alone region (SAD) of the secure storage  12 .   Contents X are recorded in the extended region (EXDS) of the secure storage  12 .   Contents X and contents Z are recorded in the extended region (EXDN) of the extended storage  30 .   Contents P are recorded in the stand-alone region (SAD) of the secure storage  12  or the extended region (EXDN) of the extended storage  30 .       

     In the above described initial state, the host device  11  is permitted to carry out the following control methods:
         To carry out the playback processing, the editing processing, the deleting processing, the moving processing and the transferring processing for the contents in the stand-alone region (SAD) of the secure storage  12     To carry out the playback processing, the editing processing, the recording processing, deleting processing, the moving processing and the transferring processing for the contents in the extended region (EXDS) of the secure storage  12  and contents in the extended region (EXDN) of the extended storage  20         

     That is, when both the secure storage  12  and the extended storage  30  are connected to the host device  11 , the host device  11  can carry out all of the processing (playback processing, editing processing, recording processing, moving processing and transferring processing). In the drawing, arrows and boxes in which names of the processing in the host device  11  are described show how contents move as a result of the processing. 
     That is, if the playback processing is carried out, the contents A in the stand-alone region (SAD) of the secure storage  12  are moved to the host device  11 . 
     If the editing processing is carried out, the contents A in the stand-alone region (SAD) of the secure storage  12  are moved to the host device  11 , and the contents A are edited to contents A′ in the host device  11 . The edited contents A′ are stored in the stand-alone region (SAD) of the secure storage  12 . 
     If the recording processing is carried out, the contents B are stored in the stand-alone region (SAD) of the secure storage  12  from the host device  11 . 
     If the deleting processing is carried out, the contents C are deleted from the stand-alone region (SAD) of the secure storage  12  for example. 
     If the moving processing is carried out, the contents C in the stand-alone region (SAD) of the secure storage  12  are read into the host device  11 , and the contents C are moved to another secure storage or another DRM. By carrying out the moving processing, the contents C are deleted from the stand-alone region (SAD). 
     If the transferring processing is carried out, the contents P in the extended region (EXDN) of the extended storage  30  are moved into the stand-alone region (SAD) of the secure storage  12  for example. By carrying out the transferring processing, the contents C are deleted from the stand-alone region (SAD). 
     The moving processing of contents in the stand-alone region (SAD) of the secure storage  12  is mainly explained in the above description. Moving processing of contents in the extended regions (EXDS) and (EXDN) are also carried out in the same manner. 
       FIG. 27  shows a first control method of the moving processing when only the secure storage  12  is connected to the host device  11 . 
     In  FIG. 27 , an initial state is the same as that shown in  FIG. 26 . In the initial state, the host device  11  is permitted to carry out the following control methods:
         To carry out playback processing, editing processing, recording processing, deleting processing, moving processing and transferring processing for contents in the stand-alone region (SAD) of the secure storage  12     To carry out the playback processing for contents in the extended region (EXDS)       

     The host device  11  can carry out the same processing for the contents in the stand-alone region (SAD) as that described above with reference to  FIG. 26 . However, for contents in the extended region (EXDS), the host device  11  is not permitted to carry out the deleting processing, the moving processing, the transferring processing and the recording processing as processing which generates addition, deletion and change of substance of the contents. 
     That is, when the same contents are copied in the secure storage  12  and the extended storage  30 , more specifically, when the contents X shown in  FIG. 27  exist in the secure storage  12  and the extended storage  30 , if the processing is carried out for the contents X, a mismatch is generated in the substance of the contents. Hence, to avoid such a case, the host device  11  is not permitted to carry out the deleting processing, the moving processing, the transferring processing and the recording processing for the contents in the extended region (EXDS). This operation manner is preferable when a data structure shown in  FIG. 30  is employed. Details there of will be described later with reference to  FIG. 30 . 
       FIG. 28  shows a second control method of the moving processing of contents when only the secure storage  12  is connected to the host device  11 . 
     In  FIG. 28 , an initial state is the same as that shown in  FIG. 27 . In the initial state, the host device  11  is permitted to carry out the following control methods:
         To carry out the playback processing, the editing processing, the recording processing, the deleting processing, the moving processing and the transferring processing for the contents in the stand-alone region (SAD) of the secure storage  12     To carry out the playback processing, the deleting processing, the moving processing and the transferring processing for the contents in the extended region (EXDS).       

     In this example, it is possible to carry out the same processing for the contents in the stand-alone region (SAD) as that described above with reference to  FIG. 27 . However, for contents in the extended region (EXDS), the host device  11  is not permitted to carry out the recording processing and the editing processing as processing which generates addition and change of substance of the contents. 
     That is, when the same contents are copied in the secure storage  12  and the extended storage  30 , more specifically, when the contents X exist in the secure storage  12  and the extended storage  30  shown in  FIG. 28 , if the contents X are edited, a mismatch is generated in the substance of the contents X in the secure storage  12  and the extended storage  30 . To avoid such a case, the host device  11  is not permitted to carry out the recording processing and the editing processing for the contents in the extended region (EXDS) of the secure storage  12 . 
     Processing which generates deletion such as the moving processing, the deleting processing and the transferring processing can relatively easily solve a mismatch. For example, since management information indicative of a list of contents is recorded in the secure storage  12 , it is possible to handle by removing contents which are deleted from the content list of the management information. 
     If an added state or an edited state is held in the management information, it is possible to carry out the processing such as the recording processing and the editing processing which are prohibited in the above description. However, if the rule “a group of contents recorded in the extended region (EXDS) of the secure storage  12  must be a subset of a group of contents recorded in the extended storage  30 ” is applied, processing for bringing the substance of contents in the extended region (EXDS) in the secure storage  12  and the substance of contents in the extended region (EXDN) in the extended storage  30  into synchronization with each other is required. Hence, since synchronization time is increased, this configuration is not preferable. 
     If this rule is not applied, the following rule can be applied to the host device  11 .
         Contents which exist only in the extended region (EXDS) in the secure storage  12  are subjected to the playback processing, the editing processing, the recording processing, the deleting processing, the moving processing and the transferring processing.       

     This operation manner is preferable when a later-described data structure shown in  FIGS. 31 and 32  is employed. 
     (Synchronization Method of Secure Storage and Extended Storage) 
       FIG. 29  shows a synchronization method of the secure storage  12  and the extended storage  30  when  FIG. 28  is applied. 
     Contents X are recorded in the extended region (EXDS) of the secure storage  12 , and contents X and contents Y exist in the extended region (EXDN) of the extended storage  30 . 
     Here, only the secure storage  12  is connected to the host device  11 , and the contents Y are subjected to any of the deleting processing, the moving processing and the deleting processing. After the processing, the secure storage  12  and the extended storage  30  are connected to the host device  11 , and the synchronization processing is carried out. 
     The host device  11  determines which one of a deleted state and a recorded state is correct as a state of the contents Y based on the management information recorded in the extended region (EXDS) of the secure storage  12 . Details of the management information will be described later. 
     As a result of determination, it is indicated in the management information that the deleted state is correct as the state of the contents Y, the host device  11  deletes the contents Y in the extended storage  30 . Here, if it is prohibited to carry out processing such as the editing processing and the recording processing for contents in the extended region (EXDS) of the secure storage  12 , it is possible to largely shorten time required for the synchronization processing. Because, the editing processing and the recording processing correspond to addition of contents which do not exist in the extended region (EXDN) of the extended storage  30  to the extended region (EXDS) of the secure storage  12 . Therefore, the synchronization processing corresponds to copying processing of contents from the secure storage  12  to the extended storage  30 . 
     Generally, video contents have large data size. Hence, time required for the copying processing of contents is not negligible, and there is a possibility that user-friendliness is largely deteriorated. Especially in the case of a consumer broadcast recorder such as a HDD recorder, when the HDD recorder is started, if the secure storage  12  and the extended storage  30  are connected to the HDD recorder, there is no means for determining whether they are continuously connected to the HDD recorder or the secure storage  12  is once detached from the HDD recorder and the editing processing or the recording processing is carried out. Hence, it is necessary to carry out the synchronization processing whenever the HDD recorder is started, and it is extremely important to shorten the time of the synchronization processing. 
     Of course, as mentioned in the description with reference to  FIG. 27 , it is preferable that the rule shown in  FIG. 28  is provided with a configuration in which an edited state and an added state are held in the management information. According to this configuration, since the synchronization processing is unnecessary in the first place, it is unnecessary to shorten the time. 
     (Example of Data Configuration) 
       FIG. 30  shows an example of data configurations of the secure storage  12  and the extended storage  30 , and includes the above described details.  FIG. 30  shows the example of detailed data configuration when the rule described with reference to  FIG. 27  is applied. 
     A content-protecting information directory exists in the stand-alone region (SAD) of the secure storage  12 . One or more content-protecting control information 000 to 002 is included below the directory. The content-protecting control information 000 to 002 has a corresponding relation with respect to the secret information existing in each of the protection regions, and the content-protecting control information 000 to 002 is referred to by later-described security information. 
     In the stand-alone region (SAD) of the secure storage  12 , one or more security information 00001 and one or more encoded contents 00001. The security information 00001 has a relation with the encoded contents 00001. Information indicative of the control information 000 to 002 is included in the security information 00001. That is, it is possible to trace secret information in the protection region which relates to decoding of encoded contents from the security information 00001 and the control information 000 to 002. 
     According to such a configuration, it is possible to control the contents of the stand-alone region (SAD). 
     One or more security information 10000 to 10001 and one or more encoded contents 10001 are included in the extended region (EXDS) in the secure storage  12 . 
     The security information 10000 to 10001 has a relation with the encoded contents 10001, and information indicative of the control information 000 to 002 is included in the security information 10001. That is, it is possible to trace secret information in the protection region which relates to decoding of encoded contents from the security information 10001 and the control information 000 to 002. 
     The encoded contents 10000 to 10001 are included in the extended region (EXDN) in the extended storage  30 . 
     Here, the security information 10000 to 10001 in the extended region (EXDS) of the secure storage  12  is associated with one or both of the encoded contents included in the extended region (EXDS) of the secure storage  12  and the encoded contents 10001 included in the extended region (EXDN) of the extended storage  30 . 
     In the extended region (EXDS) of the secure storage  12 , the security information 10000 to 10001 and the encoded contents 10001 are recorded under the directory of each of the extended storage  30 . Here, a name (secure storage xxx, secure storage yy) of the directory of the extended storage  30  corresponds to a name of the secure storage. That is, a name of a directory of the extended storage  30  is associated with information indicative of a directory described in the configuration of the link information. Hence, from the link information, the host device  11  can trace which directory information corresponds to which extended storage  30 . 
     Similarly, in the extended region (EXDN) of the extended storage  30 , the encoded contents 10000 to are recorded under the directory of each of the secure storage  12 . Here, a name of the directory of the secure storage  12  is associated with information indicative of a directory described in the configuration method of the link information. Hence, from the link information, the host device  11  can trace which directory information corresponds to which secure storage  12 . 
     These configurations include details described above, and it is possible to control contents when the rules in  FIG. 28  are applied. 
     It is also possible to divide the directory structure, and the embodiment can be realized without depending upon the configuration shown in  FIG. 30 . For example, the control information, the security information, and the encoded contents may exist under further classified directories. For example, directories which are classified for each of distributors of contents, and directories classified for each of encoding types may exist. Configurations of the classification can also be applied to later-described  FIGS. 31 and 32 . 
     The above description is made along a case where the rules shown in the description of  FIG. 27  is applied, but it is also possible to apply the rules which are made along the description of  FIG. 28 . In the rules in  FIG. 28 , it is necessary to determine which one of a deleted state and a recorded state is correct and the synchronization processing is carried out as shown in  FIG. 29 . As this method, it is possible to delete unnecessary files by comparing and referring the presence or absence of security information which is recorded in the extended region (EXDS) of the secure storage  12  and the presence or absence of the encoded contents which are recorded in the extended region (EXDN) in the extended storage  30 . 
     Further, the deleting processing and the adding processing of contents are not permitted in  FIG. 28 . However, like the determination which one of the deleting processing and the recording processing be correct, it is also possible to determine which one of the editing processing or non-editing processing is correct, or which one of the editing processing and non-editing processing is correct by comparing and referring the presence or absence of the security information which is recorded in the extended region (EXDS) of the secure storage  12  and the extended region (EXDN) in the extended storage  30 . 
       FIGS. 31 and 32  show other examples of the data configuration. 
     Examples of detailed data configurations which include the above described details and to which the rules in  FIGS. 27 and 28  are applied will be described using  FIGS. 31 and 32 . 
     In  FIG. 31 , a direction of content-protecting information exists in the stand-alone region (SAD) of the secure storage  12 . One or more content-protecting control information 000 to 001 is included under the directory. The content-protecting control information 000 to 001 has a corresponding relation with respect to the secret information existing in each of the protection regions, and the content-protecting control information 000 to 001 is referred to by a later-described security information. 
     One or more security information 00000 to 00001 exists in the stand-alone region (SAD) of the secure storage  12 . The security information 00000 to 00001 has a relation with the encoded contents 00000, and information indicative of the control information 000 to 001 is included in the security information 00000 to 00001. That is, it is possible to trace secret information in the protection region which relates to decoding of the encoded contents from the security information 00000 to 00001 and the control information 000 to 001. 
     In this example, the encoded contents 00000 are recorded under a directory of AV content. As the AV content, there is an index information file including list information of the encoded contents 00000, and the encoded contents 00000 are included under a stream information directory. Other files are also included under the AV content directory. Details thereof will be described with reference to  FIG. 32 . 
     According to such a configuration, it is possible to control contents of the stand-alone region (SAD). 
       FIG. 32  shows a configuration of the extended region (EXDS) of the secure storage  12 . 
     In  FIG. 32 , the AV content directory exists in the extended region (EXDS) of the secure storage  12 . For example, an index information file, a general information file, a menu thumbnail file, a chapter thumbnail, a play list, clip information and a stream are recorded in the AV content directory. 
     The index information file and the general information file include list information of the encoded contents. 
     The menu thumbnail file is information for a menu when a content list is displayed as a user interface. 
     In the chapter thumbnail, contents is divided for each of scenes, and thumbnail information corresponding to each of the scenes and thumbnail information at the above-described resume timing are included in the chapter thumbnail. 
     A playback pattern lying astride a portion of the encoded content, the entire encoded content or a plurality of encoded contents is recorded in the play list. 
     The clip information includes various information (length, encode state, and other information which is attendant on contents) of each of encoded contents. 
     Encoded contents and the like are recorded in the stream. 
     There is a directory of AV contents in the extended region (EXDN) in the extended storage  30 . The AV content directory includes a stream, and the stream includes a plurality of encoded contents for example. 
     Here, each of files in the extended region (EXDS) of the secure storage  12  is associated with one or both of encoded contents included in the extended region (EXDS) of the secure storage  12  and encoded contents included in the extended region (EXDN) of the extended storage  30 . 
     To realize the operation manners shown in  FIGS. 27  and  28 , a partial index information file and a partial general information file are also recorded in the AV content directory of the extended region (EXDS) of the secure storage  12  in addition to the index information file and the general information file. The partial index information file and the partial general information file include a list of encoded contents existing only in the extended region (EXDS) of the secure storage  12 . 
     That is, the index information file and the general information file include information designating all of encoded contents existing in one or both of the extended region (EXDS) of the secure storage  12  and the extended region (EXDN) in the extended storage  30 . The partial index information file and the partial general information file include information designating only encoded contents existing in the extended region (EXDS) of the secure storage  12 . According to this configuration, the host device  11  can grasp a list of encoded contents existing in each of the extended regions, and it is possible to realize the synchronization method described with reference to  FIG. 29 . In other words, as a method of determining which one of the deleted state and the recorded state is correct, it is possible to delete an unnecessary file by comparing and referring the partial index information file and the partial general information file; the index information file and the general information file; and a file recorded in the extended region (EXDN) in the extended storage  30 . 
     It is prohibited to edit and add contents in  FIG. 28 . However, like the determination which one of the deleted state and the recorded state is correct, it is possible to determine which one of the edited state and the non-edited state is correct, or which one of the added state and the non-added state is correct by comparing and referring the partial index information file and the partial general information file; the index information file and the general information file; and the file record in the extended region (EXDN) in the extended storage  30 . 
     A directory structure of the extended storage  30  designated by the link information and a directory structure of the secure storage  12  are the same as the configurations shown in  FIG. 30 . 
     According to the third embodiment, the secure storage  12  includes the stand-alone region (SAD) and the extended region (EXDS), the stand-alone region (SAD) and the extended region (EXDS) includes management information for managing contents, and the management information and the extended region (EXDS) include link information indicative of a relation with the extended storage  30 . Further, the management information of the extended region (EXDS) includes information designating only encoded contents existing only in the secure storage  12 . Therefore, even if the deleting processing, the moving processing or the transferring processing is carried out for the contents of the secure storage  12  irrespective of the extended storage  30 , the host device  11  can delete corresponding contents in the extended storage  30  based on the management information. Therefore, it is possible to easily carry out the synchronization processing between the secure storage  12  and the extended storage  30 . 
     Fourth Embodiment 
       FIGS. 33, 34 and 35  show a fourth embodiment. 
     Next, a specific mounting mode of a controller ID stored in a controller  14  will be described. 
     A controller in the embodiment stores a controller key Kc and a controller unique ID (IDcu) for identifying a content control unit  20 . 
     The secure storage of the embodiment includes an ID generator  212 , the ID generator  212  (controller identification information generator) generates a public control unique ID (IDcntr) which is sent outside while using a controller key Kc and a controller unique ID (IDcu) as input values. 
     The controller key Kc and the controller unique ID (IDcu) are written in a controller  200  as secret information by a controller vendors when the controller  200  is manufactured. The controller key Kc is commonly used by a plurality of controllers  200  due to a reason in terms of manufacturing process in some cases. Controller unique IDs differ for every controller  200 , and a controller unique key generated in a certain controller  200  is always different from a controller unique key generated by another controller  200 . 
     As shown in  FIG. 34 , a controller vendor A discloses data of a controller key Kc given to the controller  200  for a key issuing/managing center  3000 . The controller key Kc can be sent from the controller vendors A to the key issuing/managing center  3000  using PGP encoding. 
     The key issuing/managing center  3000  includes a key generator  3002  which generates a medium device key Kmd_i and a medium device key certification Cert media , a device key data base  3001  which manages the produced medium device key Kmd_i and medium device key certification Cert media , and an encoder  3003  which encodes the medium device key Kmd_i using the controller key Kc received from the controller vendor A. 
     The controller key Kc is used for encoding the medium device key Kmd_i in the key issuing/managing center  3000 . After the medium device key Kmd_i is produced by the key generator  3002 , it is stored in the device key data base  3001 . A corresponding medium device key Kmd_i is supplied from the device key data base  3001  to the encoder  3003 , it is encoded by the controller key Kc to produce an encoded medium device key Enc (Kc, Kmd_i). 
     The controller key Kc is information which is known only by the controller vendor A and the key issuing/managing center  3000 . However, to reduce damage when information of the controller key Kc leaks outside due to accident or circumstances, it is preferable change it for every controller of given amount such as manufacturing lot. 
     The key generator  3002  and the device key data base  3001  produce and manage not only the medium device key Kmd_i and medium device key certification Cert media  for the secure storage, but also a host device key Khd_i and a host device certification Certhost for a later-described host device  2000 . 
     A memory card vendor C receives, from the key issuing/managing center  3000 , supply of controller  200  from the controller vendor A, and receives a medium device key (encoded medium device key Enc (Kc, Kmd_i)) which is encoded for the controller  200  and a medium device key certification Cert media  which corresponds to the medium device key (encoded medium device key Enc (Kc, Kmd_i)). To receive a desired encoded medium device key Enc (Kc, Kmd_i), if a model number or a manufacturing lot number of the controller  200  is indicated for example, it is possible to receive a medium device key which is encoded by a correct controller key Kc. 
     The encoded (encrypted) medium device key Enc (Kc, Kmd_i) is once written in a buffer RAM  203  of the controller  200 . Then the controller  200  decodes the encoded medium device key Enc (Kc, Kmd_i) using a controller key Kc possessed by the controller  200  itself in the decoder  206 . According to this configuration, the medium device key Kmd_i is obtained in the controller  200 . 
     A unidirectional converter  211  calculates a unidirectional function using the controller key Kc and the controller unique ID (IDcu) held by the controller  200  as input values, and produces a controller unique key Kcu. The medium device key Kmd_i is again encoded in an encoder  207  using the newly produced controller unique key Kcu, and the encoded medium device key Enc (Kc, Kmd_i) is produced. The encoded medium device key Enc (Kc, Kmd_i) is stored in a system information recorder  103  of a memory  100  supplied from a memory vendor B. At this time, medium device key certification Cert media  which corresponds to the written encoded medium device key Enc (Kc, Kmd_i) is also stored in the system information recorder  103 . 
     The controller unique key (Kcu) is produced using the controller key Kc and the controller unique ID (IDcu) which are kept confidential in the controller  200 . Therefore, a risk that information which is necessary for decoding the encoded medium device key Enc (Kc, Kmd_i) leaks outside is low, and the encoded medium device key Enc (Kc, Kmd_i) which is once written in the memory  100  can be used by the other controller  200 . Hence, it is extremely difficult to improperly re-encode (after decoding using original controller unique key Kcu 1 , it is encoded using another controller unique key Kcu 2 ). 
     In this embodiment, the unidirectional function is used when the second controller unique ID (IDcntr) is produced from the controller key Kc and the first controller unique ID (IDcu), but it is only necessary that the function can produce one output data from two input data, and the function is not limited to the unidirectional function. 
     In this embodiment, the medium device key Kmd_i and the medium device key certification Cert media  which are obedience to a public key encoding system are used for exchanging processing of the authentication key. However, the controller unique ID (IDcntr) in which the controller unique ID (IDcntr) is produced based on the controller key Kc and the controller unique key Kcu of the controller  200  is supplied to the host device  2000  through a secure channel. Since the key is sent through the secure channel, the controller unique ID (IDcntr) does not leak outside, and falsification is also prevented. A memory card unique ID (IDmc) is produced by an ID coupler  403  based on the controller unique ID (IDcntr) and a medium device key certification ID (IDm_cert). A medium unique key Kmu of the memory  100  in the secure storage is produced based on the memory card unique ID (IDmc). As described above, according to the embodiment, even when the exchanging processing of the authentication key which is obedience to a public key encoding system is carried out, the pair of the public key and the secret key and the controller unique ID (IDcntr) inherent in the controller  200  can be associated with each other and this can prevent the falsification of a clone card. 
     Operation procedure when an authentication key is exchanged which is carried out based on the elliptic curve encoding will be described with reference to  FIG. 35 . 
     The host device generates a random number RNh (step S 1 ), and sends it to the secure storage together with a host device key certification Cert host  (step S 2 ). The secure storage verifies a digital signature which is given to the received host device key certification Cert host , and generates a random number RNm (step S 3 ). 
     Subsequently, the secure storage sends the random number RNm and the medium device key certification Cert media  to the host device (step S 4 ). Upon receipt of them, the host device  2000  verifies a digital signature which is given to the received medium device key certification Cert media  (step S 5 ). The secure storage carries out the processing in step S 4 , produces a random number Mk which is required for exchanging processing of a Diffie-Hellman key in the elliptic curve encoding, and calculates a challenging value Mv (=Mk*G) using an elliptic curve base point G. The ID generator  212  generates an IDcntr. The challenging value Mv, the random number RNh received in step S 2 , and a digital signature with respect to the controller unique ID (IDcntr) are produced (step S 6 ). The secure storage sends the challenging value Mv, the controller unique ID (IDcntr) and the digital signature produced in step S 6  to the host device  2000  (step S 7 ). 
     The host device  2000  verifies the signature received in step S 7 , produces a random number Hk which is required for the exchanging processing of the Diffie-Hellman key in the elliptic curve encoding, and calculates a challenging value Hv (=Hk*G) using the elliptic curve base point G. The challenging value Hv and a digital signature with respect to the random number RNm which is received in step S 4  are produced using a host device key Khd_j, and a shared key Ks (=Hk*Mv) which is shared in the exchanging processing of the authentication key is calculated (step S 8 ). The host device  2000  sends the challenging value Hv and the digital signature produced in step S 8  to the secure storage (step S 9 ). Upon receipt of them, the secure storage verifies the digital signature received in step S 9 , and calculates a shared key Ks (=Mk*Hv). When the signature is not correctly verified in the verifying process of the digital signature in the above processing, further processing is cancel no matter which step the procedure is carried out. 
     By carrying out the exchanging processing of the authentication key, the host device and the memory card vendor C can share the shared key in a confidential fashion. In the exchanging processing of the authentication key, since the shared key is calculated using the challenge mutually produced by the host device and the memory card, a value of the shared key is different whenever the exchanging processing of the authentication key is carried out. 
     Fifth Embodiment 
     Next, an embodiment of a memory ID stored in the memory  13  will be described. 
     1. Configuration Example 
     Memory System 
     A configuration example of a memory system according to the first embodiment will be described by using  FIG. 36 . 
     As shown in  FIG. 36 , the memory system according to the first embodiment includes a NAND flash memory  110  as an authenticatee, a host device  20  as an authenticator, and a controller  119  mediating therebetween. The host device  20  accesses the NAND flash memory  110  via the controller  119 . 
     Here, a manufacturing process of a semiconductor product such as the NAND flash memory  110  will briefly be described. The manufacturing process of a semiconductor product can mainly divided into a preprocess to form a circuit on a substrate wafer and a postprocess to cut the wafer to individual pieces and then to perform wiring and packaging a piece in a resin. 
     The controller  119  is configured in various ways such being configured to be included in the NAND flash memory  110  in the preprocess, configured to be included in the same package in the postprocess, though not included in the preprocess, and provided as a different chip from the NAND flash memory  110 . The description below including  FIG. 36  is provided by taking a case when the controller  119  is provided as a different chip from the NAND flash memory  110  as an example. 
     If not mentioned specifically below, the controller  119  mediates between the host device  20  and the NAND flash memory  110  in many cases to exchange data and instructions therebetween. Even in such a case, the controller  119  does not change intrinsic content of the above data and instructions and thus, details may be provided below as an abbreviated description. Details of configuration examples of the NAND flash memory  110  and the controller  119  will be provided later. 
     If the host device  20  is configured as dedicated hardware like a consumer device, not only a case where the device is configured by combining dedicated hardware with firmware to operate the dedicated hardware, but also a case where all functions of the device are realized by software operating in a PC can be assumed. The present embodiment can basically be applied regardless of which configuration the host device  120  adopts. 
     Each component and data processing shown in  FIG. 36  will be described below. The present embodiment shows the method of reading secret identification information SecretID recorded in an authenticatee in a state hidden from third parties and also verifying that the data has been read from an authentic authenticatee and a configuration example when the method is applied to a memory system using the NAND flash memory  110 . 
     1-1. NAND Flash Memory 
     In the present embodiment, the NAND flash memory  110  is an authenticatee. 
     As shown in  FIG. 36 , the NAND flash memory  110  according to the present embodiment includes a cell array (Cell array)  111 , a data cache (Data Cache)  112  disposed in a peripheral area of the cell array  111 , data generators (Generate)  113 ,  114 , and a one-way converter (Oneway)  115 . The data generators (Generate)  113 ,  114  and the one-way converter (One-way)  115  constitute an authentication circuit  117 . 
     The cell array  111  includes a read/write area (Read/Write area)  111 - 1  permitted to read and write into from outside, a hidden area (Hidden area)  111 - 2  inhibited from both reading and writing into from outside, and a ROM area (ROM area)  111 - 3  inhibited from writing into from outside. 
     The read/write area (ordinary area)  111 - 1  is an area into which data can be written and from which data can be read from outside the NAND flash memory  110 . In the read/write area  111 - 1 , key management information FKBv (Family Key Block) that is an encrypted FKey bundle prepared to hide FKeyv is stored. In contrast to other data recorded in the NAND flash memory  110 , FKBv may be record when the NAND flash memory  110  is fabricated, or when the storage media for general user is fabricated by connecting the controller to the NAND flash memory  110 . Alternatively, FKBv may be downloaded from a server in accordance with a user&#39;s request after shipping. That is, a third memory area  111 - 1  is used to store a family key block FKB including data generated by encrypting the family key FKey with a host identification key IDKey, the third memory area  111 - 1  being required to be readable and writable from outside of the authenticator. Details thereof will be described below. 
     The key management information FKBv is information used to decrypt hidden information FKeyv based on secret information IDKeyk held by the host device  120  and index information k of the secret information IDKeyk, or information used to decrypt hidden information FKeyv based on secret information IDKeyk held by the host device  120  and identification information of the host device  120 . 
     The key management information FKBv is also information not only prepared uniquely for each of the NAND flash memories  110 , but also can be commonly attached to (can be associated with) a plurality of the NAND flash memories  110  such as the production lot unit or wafer unit of the NAND flash memories  110  in accordance with the manufacturing process. Index information v of the key management information FKBv may be identification information or version number information of the key management information FKBv. 
     The hidden area  111 - 2  is an area inhibited from both reading and writing into from outside the NAND flash memory  110 . In the hidden area  111 - 2 , secret information NKeyi used by the NAND flash memory  110  for an authentication process and secret identification information SecretID of the NAND flash memory  110  are recorded. 
     The ROM area  11 - 3  is an area inhibited from writing into from outside the NAND flash memory  110 , but is permitted to read data therefrom. In the ROM area  111 - 3 , index information v (index of FKey) to indicate hidden information FKeyv hidden by the key management information FKBv, secret identification information (SecretID) encrypted by the hidden information Fkeyv (E-SecretID), and index information i (index of NKey) to indicate the secret information NKeyi are recorded. 
     In the present embodiment, data is generally recorded after an error correction code being attached so that, even if an error occurs in data when the index information i or the index information v is recorded, correct identification information can be read. However, to simplify the description, error correction encoding and decoding processes are not specifically illustrated. 
     Incidentally, the ROM area  111 - 3  may be, for example, an OTP (One Time Program) area into which data is permitted to write only once or an ordinary area permitted to read and write into in the manufacturing process of the NAND flash memory  110  before being converted into a read-only area by rewriting a management flag after shipment. Alternatively, a method may be used in which the specific write command for accessing to the ROM area and different to the command for accessing to the normal area is prepared, and this specific write command is not provided to the recipient of the NAND flash memory  110 . In addition, the ROM area may be handled as an ordinary area in the NAND flash memory  110 , but the controller  119  limits functions provided to the host device  120  to reading only. 
     Because, as will be described below, information recorded in the ROM area  111 - 3  is associated with information recorded in the hidden area  111 - 2 , if information recorded in the ROM area  111 - 3  is tampered with, the authentication function of the NAND flash memory  110  cannot be made to work effectively. Therefore, there is no cause for security concern due to tampering and thus, the ROM area  111 - 3  may be replaced with an ordinary area in which the reading and writing data is permitted. In such a case, the ROM area  111 - 3  in  FIG. 36  may be replaced with the read/write area (ordinary area)  111 - 1 . In this connection, a portion of data recorded in the ROM area  111 - 3  may be recorded in the read/write area (ordinary area)  111 - 1 . For example, a configuration in which index information v (index of FKey) is recorded in the read/write area (ordinary area) and encrypted secret identification information (E-SecretID) and index information v (index of FKey) are recorded in the ROM area  111 - 3  is allowed. The above configuration examples of the ROM area  111 - 3  are also applicable to the ROM area  111 - 3  described herein as other embodiments or modifications below. 
     E-SecretID is data obtained by encrypting SecretID attached uniquely to each of the NAND flash memories  110  by FKeyv. Alternatively, the same encrypted secret identification information may be recorded in a plurality of NAND flash memories as usage. For example, in pre-recording content distribution, the same content data is recorded in NAND flash memories in advance to sell the NAND flash memories, and the same E-SecretID is recorded in the NAND flash memories storing the content. 
     The data cache  112  temporarily stores data read from the cell array  111 . 
     The data generators  113 ,  114  are circuits that generate output data from a plurality of pieces of input data by a preset operation. 
     The data generator  113  generates secret information HKeyi,j by converting a constant HCj received from the host device  120  by using the above secret information NKeyi. The data generator  114  generates a session key SKeyi,j by converting a random number RNh received from the host device  120  by using the secret information HKeyi,j. The data generators  113 ,  114  can be implemented as hardware (circuit), software, or a combination of hardware and software. 
     If the data generators  113 ,  114  are implemented as circuits, the same circuit as the one-way converter  115  described below, a circuit diverting the one-way converter, or an Advanced Encryption Standard (AES) encryptor can be used to make the circuit size smaller as a whole. Similarly, the same circuit can be used repeatedly for two data generators illustrated as different structural elements to make the data processing procedure easier to understand. In this example, a configuration of HKeyi,j=AES_E (NKeyi, HCj), SKeyi,j=AES_E (HKeyi,j, RNh) and the like can be adopted. That is, a first data generator  13  is configured to generate a second key HKey by encrypting a host constant HC with the first key NKey in AES operation. A second data generator  114  is configured to generate a session key SKey by encrypting a random number RN with the second key HKey in AES operation. 
     The one-way converter  115  performs a one-way conversion on input data and key data input separately to output one-way converted input data. The one-way converter  115  can be implemented as hardware (circuit), software, or a combination of hardware and software. 
     The one-way converter  115  converts the SecretID read from the hidden area  111 - 2  by a one-way function using the SKeyi,j generated by the data generator  114  to generate one-way conversion identification information Oneway-ID (=Oneway(SKeyi,j, SecretID)). If implemented as a circuit, the one-way converter  115  can also be used by diverting the data generator  114  or the like to make, as described above, the circuit size smaller as a whole. In this example, a configuration like Oneway-ID=AES_E(SKeyi,j, SecretID) (+) SecretID can be adopted. 
     Though not shown, an output unit to output data to the host device  120  via the controller  119  and like are actually arranged as structural elements. 
     1-2. Host Device 
     In the present embodiment, the host device  120  is an authenticator. 
     As shown in  FIG. 36 , the host device  120  according to the present embodiment includes a decrypter (Decrypt)  121 , an FKB processor (Process FKB)  122 , a memory (Memory)  123 , a random number generator (RNG)  124 , a selector (Select 2) 125, a data generator (Generate)  126 , a one-way converter (Oneway)  127 , and a data verification unit (Verify)  128 . In addition, for example, an error correction processing unit and the like may be included if necessary. 
     The decrypter  121  decrypts input data by using key data input separately to output decrypted input data. In the present embodiment, the decrypter  121  reads E-SecretID from the NAND flash memory  110  via the controller  119 . Then, the decrypter  121  decrypts the E-SecretID by using hidden information FKey input from the FKB processor  122  (data selector  122 - 1 ) described below to output SecretID. 
     The FKB processor  122  decrypts key management information FKBv read from the NAND flash memory  110  by using secret information IDKeyk and index information k of the IDKeyk hidden in the memory  123  to output generated hidden information FKey to the decrypter  121 . In the present embodiment, the FKB processor  122  includes a data selector (Select 1)  122 - 1  and a decrypter (Decrypt)  122 - 2 . 
     The data selector  122 - 1  in the first stage selects data that can be decrypted by IDKeyk hidden in the memory  123  by using index information k recorded in the memory  123  from among an encrypted FKey bundle (key management information FKBv) read from the NAND flash memory  110  and outputs the selected data to the decrypter  122 - 2 . 
     The decrypter  122 - 2  decrypts data selected by the data selector  122 - 1  by using the IDKeyk hidden in the memory  123  to output generated hidden information FKey to the decrypter  121 . 
     The memory  123  records k, IDKeyk, set of HKeyi,j (i=1, . . . , m; j is a fixed value for HKeyi,j), and HCj and hides at least IDKeyk and set of HKeyi,j (i=1, . . . , m) from outside the host device  120 . The HCj is a constant held in the host device  120  in advance to be sent to the NAND flash memory  110  when authentication is requested (Request authentication). Details thereof will be described below. 
     The random number generator  124  generates and outputs a random number RNh used for an authentication process. 
     The data selector  125  in the second stage selects HKeyi,j needed for the authentication process from the set of HKeyi,j hidden by the host device  120  by using index information i read from the ROM area  111 - 3  of the NAND flash memory  110  via the data cache  112 . 
     The data generator  126  is an operation unit that generates output data by performing a predetermined operation on a plurality of pieces of input data. In the present embodiment, the data generator  126  generates a session key SKeyi,j by converting RNh generated by the host device  120  by using HKeyi,j hidden by the host device  120 . As the data generator  126 , for example, the above AES encryptor may be used. 
     The one-way converter  127  converts SecretID output from the decrypter  121  by a one-way function using SKeyi,j output from the data generator  126  to generate one-way conversion identification information Oneway-ID. 
     The data verification unit  128  compares Oneway-ID received from the NAND flash memory  110  and Oneway-ID obtained from the one-way converter  127  in the host device  120  to see whether both Oneway-IDs match. If both values of the one-way conversion identification information Oneway-ID match (OK), the data verification unit  128  judges that SecretID obtained by the decrypter  121  is an authentic ID and delivers the obtained SecretID to subsequent processes. On the other hand, if both values thereof do not match (NG), the data verification unit  128  judges that the SecretID is an unlawful ID and outputs a message to that effect. 
     In addition, as means for revoking an unlawful host device when secret information held by the host device  120 , for example, IDKeyk and HKeyi,j are leaked and the unlawful host device having the leaked information is produced by an illegal vendor, countermeasures such as removing information from the key management information (FKBv) with which FKey can be derived from IDKeyk held by the unlawful host device. The countermeasures will be described below in connection with the description with reference to  FIG. 38 . When taking the countermeasures, it is useful to provide association among IDKeyk, k, HKeyi,j, and HCj. This is because if there is such association, both of secret information IDKeyk and HKeyi,j held by the unlawful host device can be identified by observing HCj notified by the unlawful host device for authentication. Sharing information of all or a portion of HCj with IDKeyk, configuring information of all or a portion of HCj based on a result of an encryption process of IDKeyk, and configuring information of all or a portion of IDKeyk based on a result of an encryption process of HCj can be adopted as methods of association. Further, it is desirable to use HKeyi,j, in addition to FKey and IDKeyk to generate key management information FKBv. This will be described below in a paragraph in which a configuration example of FKB is described. 
     The secret information IDKeyk and secret information HKeyi,j are recorded, for example, after being encrypted by a method specific to the vendor in an internal dedicated memory if the host device  120  is a dedicated hardware device like a consumer device, held in a state that can be protected from an unlawful analysis by tamper resistant software (TRS) technology if the host device  120  is a program executed in a PC or the like, or recorded in a state after measures to hide the secret information being taken by using the function of a security module if the security module is contained. 
     The controller  119  performs data transfer with the host device  120  by controlling the NAND flash memory  110 . For example, the controller  119  interprets an instruction received from the host device  120  and converts the instruction into an instruction conforming to the interface specifications of the NAND flash memory  110  before sending out the instruction to the NAND flash memory  110 . The controller  119  can adopt various interface standards such as the SD Memory standard, SDIO standard, and eMMC standard if necessary. 
     The controller  119  secures a portion of the ordinary area  111 - 1  to store control data needed for the operation of the controller  119 . The controller  119  may have a function to convert a logical address received from the host device  120  into a physical address of the NAND flash memory. The controller  119  may also have a function to perform the so-called wear leveling to make exhaustion of the cell array  111  uniform. However, at least the hidden area  111 - 2  is excluded from wear leveling. 
     The configuration example of the memory system is not limited to the one described above. For example, an error correction processing unit (not shown) and other structural elements may be included if necessary. Further, there may be a plurality of pieces of secret information NKeyi held by the NAND flash memory  110 . That is, if a combination of NKeyi and index information i corresponding thereto is defined as a slot, a plurality of slots is recorded in the NAND flash memory  110 . A slot number is attached to each of the slots and the host device  120  reads index information i of each slot number and selects one of the slots to perform authentication. In this case, the host device  120  notifies the NAND flash memory  110  of information corresponding to the selected slot number and the NAND flash memory  110  executes an authentication process by using information corresponding to the notified slot number. Further, a plurality of information slots may be held by defining all information held by the NAND flash memory  110  as one slot. That is, NKeyi, i, FKBv, v (index of FKey), SecretID, and E-SecretID are defined as one slot and a plurality of slots is recorded in the NAND flash memory  110 . A slot number is attached to each of the slots and the host device  120  reads index information i of each slot number and selects one of the slots to perform authentication. In this case, the host device  120  notifies the NAND flash memory  110  of information corresponding to the selected slot number and the NAND flash memory  110  executes an authentication process by using information corresponding to the notified slot number. 
     The method by which the NAND flash memory  110  has a plurality of slots is shown above, but the method is not limited to the above one and any configuration sharing a portion of information by a plurality of slots can be adopted. For example, SecretID, E-SecretID, FKBv, and index v may be shared by a plurality of slots while other information being individually held by each slot. 
     The method by which the NAND flash memory  110  has a plurality of slots and slot numbers and which slot to use for authentication is notified by the host device  120  is applicable to all other embodiments described herein below. 
     &lt;2. Authentication Flow&gt; 
     Next, the authentication flow of a memory system according to the fifth embodiment will be described along  FIG. 37 . 
     (Step S 111 ) 
     When the authentication is started (Start), the host device  120  reads an encrypted FKey bundle (FKB: Family Key Block), which is key management information, and encrypted secret identification information SecretID (E-SecretID) from the NAND flash memory  110 . 
     (Step S 112 ) 
     Subsequently, the host device  120  reads encrypted hidden information FKey that can be decrypted by the host device  120  by executing a data selection process by the data selector (Select 1)  122 - 1  from the read key management information FKB and also obtains hidden information FKey by decrypting the encrypted hidden information FKey by the decrypter  122 - 2  using hidden secret information IDKeyk. Further, the host device  120  obtains secret identification information SecretID by decrypting the E-SecretID read from the NAND flash memory  110  using the obtained FKey. 
     (Step S 113 ) 
     Subsequently, the host device  120  requests to read index information i to the NAND flash memory  110 . 
     (Step S 114 ) 
     Subsequently, in response to the request from the host device  120 , the NAND flash memory  110  loads the index information i from the cell array  111  and outputs the index information i to the host device  120 . 
     (Step S 115 ) 
     Subsequently, the host device  120  generates a random number RNh needed for an authentication request. By using RNh for the authentication process, a common key that is different each time can be used with the NAND flash memory  110  for processes below. 
     (Step S 116 ) 
     Subsequently, the host device  120  sends out a constant HCj held in advance and the RNh to the NAND flash memory  110  along with the a Request authentication. 
     (Step S 117 ) 
     Subsequently, the NAND flash memory  110  loads secret information NKeyi (i=1, . . . , m) and secret identification information SecretID from the hidden area  111 - 2 , which are stored in the data cache  112 . 
     (Step S 118 ) 
     Subsequently, the NAND flash memory  110  generates secret information HKeyi,j by a data generation process of the data generator  13  using the hidden secret information NKeyi and the constant HCj received from the host device  120 . 
     (Step S 119 ) 
     Subsequently, the NAND flash memory  110  generates a session key SKeyi,j (=Generate(HKeyi,j, RNh)) by a data generation process of the data generator  114  using the received RNh. 
     (Step S 120 ) 
     Subsequently, the NAND flash memory  110  generates one-way conversion identification information Oneway-ID (=Oneway(SKeyi,j, SecretID)) by executing a one-way conversion process of the one-way converter  115  on the SecretID using the SKeyi,j. The generated Oneway-ID is sent out to the host device  120 . 
     (Step S 121 ) 
     In parallel with step S 118 , the host device  120  selects HKeyi,j needed for an authentication process with the NAND flash memory  110  from the set of HKeyi,j (i=1, . . . m) hidden in advance using the received index i. 
     (Step S 122 ) 
     Subsequently, the host device  120  generates the SKeyi,j (=Generate(HKeyi,j, RNh)) by a data generation process of the data generator  126  using the selected HKeyi,j and the generated RNh. 
     (Step S 123 ) 
     Subsequently, the host device  120  generates Oneway-ID by executing a one-way conversion process of the one-way converter  127  on the SecretID using the generated SKeyi,j. 
     (Step S 124 ) 
     Subsequently, the host device  120  determines whether the Oneway-ID received from the NAND flash memory  110  and the Oneway-ID generated by the host device  120  match. If both values of the Oneway-ID match (OK), the host device  120  judges that the SecretID obtained by the decrypter  121  is an authentic ID and delivers the SecretID to subsequent processes. On the other hand, if both values thereof do not match (NG), the host device  120  judges that the SecretID is an unlawful ID and outputs a message to that effect. 
     With the above operation, the authentication flow according to the first embodiment is completed (End). 
     If the NAND flash memory  110  has a plurality of slots as described in a configuration example of the memory system, the host device  120  needs to notify the NAND flash memory  110  of the slot number used for authentication. In such a case, the slot number may be notified in step S 116  or in a step before step S 161 . 
     &lt;3. FKB (Family Key Block)&gt; 
     Next, key management information FKB (Family Key Block) according to the fifth embodiment will be described in more detail by using  FIG. 38 . 
     To generate key management information FKB conforming to the NAND flash memory  110  in which secret identification information SecretID is recorded, one piece of FKeyv after another is encrypted (Encrypt) by using one IDKeyi (i=1, . . . , n) (Set of IDKeyi&#39;s) after another as secret key information prepared in advance. That is, the key management information FKB is a set of encrypted FKeyv (E-FKeyv,i)=Encrypt (IDKeyi, FKeyv) and the set of encrypted FKeyv is called an encrypted FKey bundle. 
     Incidentally, the configuration of the key management information FKB is not limited to the configuration in the present embodiment. For example, in case where the specific IDKeyi is leaked, encrypted FKeyv (E-FKeyv) which can be decrypted from the leaked IDKeyi is deleted from the FKB. As a result, when the host device  120  accesses the NAND flash memory  110  with the newly configured FKB, the host device  120  can not obtain (decrypt) correct FKeyv and SecredID. In this manner, the function to revoke the host device  120  holding the secret information IDKeyi can be provided. 
     When, as described above, IDKeyk, k, HKeyi,j, and HCj are associated, HKeyi,j may also be diverted, in addition to FKey and IDKeyk, for the generation of FKBv. For example, configurations such as E-FKeyv,i=Encrypt (Encrypt(IDKeyi, FKeyv), HKeyi,j), E-FKeyv,i=Encrypt (Encrypt(HKeyi,j, FKeyv), IDKeyi), and E-FKeyv,i=Encrypt(HKeyi,j, IDKeyi(+)FKeyv) may be adopted. This has the effect of preventing, when keys are leaked from a plurality of the host devices  20 , the secret keys IDKeyi, HKeyi,j of different devices being combined. That is, by making decryption of FKey impossible unless IDKeyi and HKeyi,j are correctly combined, observing HCj reveals tied HKeyi, j and further IDKeyi can be identified so that exposed IDKeyi can be revoked. 
     Further, the method of generating the key management information FKB is not limited to the method in the present embodiment. For example, the function to revoke the host device  120  can also be provided if the key management information FKB is generated by using conventional MKB (Media Key Block) technology used in CPRM or another MKB technology. 
     The MKB technology efficiently shares common secret information (Media Key) (among devices not to be revoked) while realizing device revocation in a situation in which each of a plurality of devices has a mutually different piece of secret information and is also called Broadcast Encryption. 
     If the MKB technology is applied, for example, a configuration example of the memory system is shown like in  FIG. 39 . The shown memory system is different from the memory system in  FIG. 36  in that the FKB processor (Process FKB)  22  is shown as a superordinate concept. Also in this case, the exposed key can be identified and revoked by associating the data of FKB decrypted based on the node number of the host device  120  that is information corresponding to K or IDKeyi and a host key group allocated to the node number with HKeyi,j and HCj. 
     &lt;4. Writing Secret Information and FKB&gt; 
     Next, writing secret information or key management information FKB into the NAND flash memory  110  will be described. 
     4-1. When Writing Secret Information or Key Management Information FKB During Manufacture of the NAND Flash Memory 
     First, a case where secret information or key management information FKB is written, for example, during manufacture of the NAND flash memory  110  will be described by using  FIGS. 40 and 41 . The description will be provided along the flow in  FIG. 41 . 
     A licensing administrator  140  generates data below: key management information FKBv (v=1, . . . , n), hidden information FKeyv (v=1, . . . , n), index information v (v=1, . . . , n), secret information NKeyi, and index information i. FKBv is generated by, as described above, encrypting FKeyv. In addition, v may be a plurality of values. If, for example, the licensing administrator  140  generates three values of 1, 2, and 3 as v, the licensing administrator  140  generates (FKB1, FKey1), (FKB2, FKey2), and (FKB3, FKey3) in accordance with the generated v. 
     Of the generated data, the licensing administrator  140  delivers FKeyv (v=1, . . . , n), v (v=1, . . . , n), NKeyi, i to a memory vendor  130 . For the delivery the data, for example, the licensing administrator  140  uses safe means such as sending the data to the memory vendor  130  after the data being encrypted by using a public key of the memory vendor  130  obtained in advance. 
     In the memory vendor  130 , there are selectors  132 ,  133 , a generator  134 , and an encryption unit  135 , in addition to the NAND flash memory  110 . The memory vendor  130  further holds data  131  such as FKBv (v=1, . . . n) delivered by the licensing administrator  140 . 
     (Step S 131 ) 
     With the above configuration, the memory vendor  130  first generates SecretID by the generator (SecretID Generator)  134 . 
     (Step S 132 ) 
     Subsequently, the memory vendor  130  that receives the data  131  selects one value from v by the selector  132 . Further, the selector  132  selects FKeyv corresponding to the selected v. The memory vendor  130  encrypts the generated SecretID to generate E-SecretID by using the selected FKeyv. 
     (Step S 133 ) 
     Subsequently, the memory vendor  130  writes the value of v into the ROM area  111 - 3  of the NAND flash memory  110  as the index information v (index of FKey). 
     The memory vendor  130  also writes the value of index information i (index of NKey) into the ROM area  111 - 3  of the NAND flash memory  110  and the value of NKeyi into the hidden area  111 - 2 . 
     Further, the memory vendor  130  writes the value of SecretID into the hidden area  111 - 2  of the NAND flash memory  110  and the value of E-SecretID into the ROM area  111 - 3 . 
     With the above operation, predetermined secret information and key management information FKB can be written during manufacture of the NAND flash memory  110  (End). Regarding the order of writing each of the above values, E-SecretID is a value obtained after an encryption process and can be written after the encryption process by the encryption unit  135 . Otherwise, there is no restriction on the order of writing operation and the values may be written in an order different from the order of the above example. 
     Further, the memory vendor  130  delivers the NAND flash memory  110  for which the write process is completed to a card vendor. 
     Thus, in the present embodiment, the NAND flash memory  110  can be assumed to be in a state in which index information v (index of FKey) or the like is already written. 
     4-2. When FKB is Written by the Card Vendor 
     Next, a case where a card vendor  150  writes FKB will be described by using  FIGS. 42 and 43 . The description will be provided along the flow in  FIG. 43 . 
     The card vendor  150  receives the NAND flash memory  110  to which the predetermined information v and the like have been written from the memory vendor  130 . 
     Then, the card vendor  150  manufactures storage media (here, Card)  155  for general users like, for example, SD cards by connecting the controller  119  that controls the NAND flash memory  110 . 
     In the card vendor  150 , there is a selector  152 , in addition to the storage media (Card)  155  and data (FKBv)  151  received from the licensing administrator  140 . 
     The process to write key management information FKBv by the card vendor  150  is as follows. 
     (Step S 135 ) 
     First, the card vendor  150  receives the FKBv from the licensing administrator  140  as the data  151 . For the delivery of the data  151 , the above safe means is used. 
     Then, the card vendor  150  reads the value of the index information v recorded in the ROM area  111 - 3  of the NAND flash memory  110  into the data cache  112  or the like (via the controller  119 ). 
     (Step S 136 ) 
     Subsequently, the card vendor  150  selects the FKBv corresponding to the value of the read index information v through the selector  152 . 
     (Step S 137 ) 
     Subsequently, the card vendor  150  writes the selected FKBv into the read/write area  111 - 1  of the NAND flash memory  110  via the controller  119 . 
     Advantageous Effects 
     According to the authenticator, authenticatee and authentication method according to the first embodiment, at least the following advantageous effects (1) to (3) can be obtained. 
     (1) Even if Secret Information has Leaked from the Host Device  120 , it is Possible to Prevent Unlawful Use Of Secret Information of the NAND Flash Memory  110  Using the Leaked Information. 
     The host device  120  as an authenticator may be provided, as described above, not only as a dedicated hardware device such as a consumer device, but also, for example, as a program executable in a PC or the like, and, in some cases, the software functions as a substantial host device. On the other hand, the NAND flash memory  110  as an authenticatee is recording media. Even in the case where a program called “firmware” mediates, an important process or information is stored in a hidden state in hardware in the cell array  111 . 
     Thus, there is concern that the tamper-resistance (the resistance to attacks) of software executed in a PC becomes lower, compared to the recording media. Thus, there is concern that, by attacking the host device (authenticator)  120  with a low tamper-resistance, secret information hidden in the NAND flash memory (authenticatee)  110  with a high tamper-resistance is also exposed, leading to a disguise as a device with a high tamper-resistance. 
     Thus, in the configuration according to the fifth embodiment and the authentication method therefor, as described above, the NAND flash memory  110  with a relatively high tamper-resistance hides first key information (NKeyi) that can generate second key information (HKeyi,j) therefrom in the cell array  111 . On the other hand, the host device  120  hides only the second key information (HKeyi,j) that cannot generate the first key information (NKeyi) therefrom in the memory  123 . 
     Thus, the NAND flash memory  110  generates the second key information (HKeyi,j) hidden by the authenticator  20  by using the constant HCj received from the host device  120  and the first key information (NKeyi) hidden by the NAND flash memory  110 . The NAND flash memory  110  further generates a session key SKeyi,j using the second key information (HKeyi,j) and the random number RNh. 
     The host device  120  generates a session key SKeyi,j using the second key information (HKeyi,j) selected by the index information i and the random number RNh. As a result, the NAND flash memory  110  and the host device  120  share the same session key SKeyi,j. 
     Thus, in the present embodiment, the secret level of information hidden by the NAND flash memory (authenticatee)  10  and the secret level of information hidden by the host device (authenticator)  120  can be made asymmetric. In the present embodiment, for example, the secret level of information hidden by the NAND flash memory  110  with a relatively high tamper-resistance can be set higher than the secret level of information hidden by the host device  120  with a relatively low tamper-resistance. 
     Thus, even if information hidden by the host device  120  has leaked, the NAND flash memory  110  cannot be “disguised” by using the leaked information because the secret level of information hidden by the NAND flash memory  110  with a relatively high tamper-resistance is higher. Therefore, unlawful use of secret information of the NAND flash memory  110  using the leaked information can advantageously be prevented. As a result, for example, it becomes possible to reliably determine that ID information read from the host device  120  is information that has been read from the intended authenticatee  110  and to revoke unlawful use thereof by remote parties. 
     (2) Advantages for Implementation 
     In a configuration like the present embodiment, as described above, restrictions are also imposed on circuit scales, for example, in an environment in which hardware implementation of a public key cryptosystem process or an MKB process, which requires a relatively large circuit scale, is difficult to achieve. 
     However, according to the present embodiment, though the key information is asymmetric, there is no need to use the public key cryptosystem process requiring a relatively large circuit scale. Further, by making the secret levels of information hidden by the host device (authenicator)  120  and the NAND flash memory (authenticatee)  110  asymmetric as described above, authentication means is implemented by which with information leaked from one device alone, the other device cannot be disguised and the session key SKeyi,j is shared by the authenticator  120  and the authenticatee  110 . 
     Thus, implementation can be said to be advantageous even in a severe environment in which the above restrictions are imposed. Further, as described above, the circuit scale can be further reduced by sharing the data generator and encryptor in a memory system as the same process. 
     (3) The Manufacturing Process can Advantageously be Simplified and Manufacturing Costs can be Reduced. 
     The NAND flash memory  110  according to the present embodiment includes in the read/write area  111 - 1  key management information (FKBv) attached uniquely to each of the NAND flash memories  110  in accordance with uses thereof or commonly to a plurality of the NAND flash memories  110  in units of the production lot or the like. Further, the NAND flash memory  110  according to the present embodiment includes in ROM area  111 - 3  encrypted secret identification information (E-SecretID) attached uniquely to each of the NAND flash memories  110 . 
     If the key management information (FKBv) is made common in units of the production lot, unique information that needs to be recorded in each of the NAND flash memories  110  can be reduced to small data in data size such as the encrypted secret identification information (E-SecretID). In other words, the data size of unique encrypted secret identification information (E-SecretID) to be written into the NAND flash memories  110  can be reduced by dividing information to be written into commonly attached key management information (FKBv) and unique encrypted secret identification information (E-SecretID) and encrypting the information in two stages. 
     For example, as shown in  FIGS. 40 and 41  above, the memory vendor  130  writes unique information (E-SecretID) into each of the NAND flash memories  110  received from the licensing administrator  140  during manufacture of the NAND flash memories. 
     The encrypted key management information (FKBv) commonly attached to the NAND flash memories  110  can commonly be written into the NAND flash memories  110  by the card vendor  150 . For example, as shown in  FIGS. 42 and 43  above, the card vendor  150  writes the common key management information FKBv to each of the NAND flash memories  110  received from the licensing administrator  140 . Thus, the size of unique data that must be written into each of the NAND flash memories  110  by the memory vendor  130  can be reduced. 
     If information unique to the NAND flash memory  110  and whose data size is large is written during manufacture of the NAND flash memories  110 , the manufacturing process will be more complex and the manufacturing time will be longer, leading to increased costs of manufacturing. According to the configuration and method in the present embodiment, however, such a complex manufacturing process becomes unnecessary by dividing information to be written into commonly attached key management information FKBv and unique encrypted secret identification information (E-SecretID) and encrypting the information in two stages and therefore, the manufacturing process can advantageously be simplified and manufacturing costs can be reduced. Moreover, the manufacturing time can be shortened, offering advantages of being able to reduce power consumption. 
     Also on the side of the host device  120 , advantages similar to those of the NAND flash memory  110  can be gained by adopting a configuration of generating E-SecretID by encrypting SecretID, which is a unique value to the NAND flash memory, by using hidden information FKey and further generating key management information FKB by encrypting FKey using IDKeyk. 
     First Modification 
     When FKB is Downloaded and Written Later 
     An authenticator, an authenticatee, and an authentication method according to a first modification will be described. In the description, overlapping points with the first embodiment will be omitted. 
     &lt;Writing FKB&gt; 
     Writing an encrypted FKey bundle (FKB) will be described. 
     The process in the first modification is a process that is not particularly needed if the encrypted FKey bundle (FKB) is written during manufacture of the NAND flash memory  110 . However, the process relates to a write process of FKB needed when the NAND flash memory  110  and the controller  119  are connected and the NAND flash memory  110  is acquired by a general user as, for example, an SD card and FKB is written later on the market when the card is used. 
       FIG. 44  shows a state in which the key management information FKB is, as described above, recorded in the unrecorded storage media (Card)  55 . 
     As shown in  FIG. 44 , the NAND flash memory  110  has NKeyi and SecretID recorded in the hidden area  111 - 2 . Index information i needed to identify the NKeyi, index information v needed to identify FKB, and SecretID (E-SecretID) encrypted by FKeyv specified by the index information v are recorded in the ROM area  111 - 3 . 
     The first modification is different from the first embodiment in that the FKB, which is an encrypted FKey bundle, is not recorded in the read/write area  111 - 1 . 
     Next, a case where the FKB is, as described above, downloaded from a server and recorded in the unrecorded storage media  55  will be described by using  FIG. 45 . 
     In this case, as shown in  FIG. 45 , the data cache  112  is arranged in the NAND flash memory  110  if necessary. 
     A server  170  according to the present embodiment includes an FKB data base (Set of FKBi&#39;s (i=1, . . . , x))  171  and a selector  172  to select FKBv based on index information v. 
     The server  170  and the memory system (the NAND flash memory  110 , the controller  119 , and the host device  120 ) are electrically connected for communication via an Internet  160 . 
     The host device  120  includes a function to determine whether it is necessary to newly write FKB and to request FKB from the server if necessary. 
     &lt;FKB Write Flow&gt; 
     Next, the flow to download an encrypted FKeyID bundle (FKB) from the server  170  and to write the FKB into the NAND flash memory  110  will be described along  FIG. 46 . 
     (Step S 141 ) 
     First, as shown in  FIG. 46 , when the host device  120  determines that it is necessary to download FKB, FKB writing is started and the host device  120  issues an FKB request to the server  170 . 
     (Step S 142 ) 
     Subsequently, the server  170  requests index information v needed to identify FKeyv from the NAND flash memory  110 . 
     (Step S 143 ) 
     Subsequently, the NAND flash memory  110  reads v from the ROM area  111 - 3  and sends out v to the server. 
     (Step S 144 ) 
     Subsequently, the server  170  selects FKBv corresponding to the received v from the FKB database  171 . 
     (Step S 145 ) 
     Subsequently, the server  170  sends out the selected FKBv to the NAND flash memory  110 . 
     (Step S 146 ) 
     Subsequently, the NAND flash memory  110  writes the received FKBv into the read/write area  111 - 1  for recording. 
     With the above operation, the download flow of the encrypted FKey bundle (FKB) according to the first modification is completed (End). 
     Other configurations and operations are substantially the same as those in the first embodiment. 
     Advantageous Effects 
     According to the authenticator, authenticatee and authentication method according to the first modification, at least the advantageous effects (1) to (3) similar to those in the first embodiment can be obtained. 
     Further, according to the first modification, the present embodiment can be applied if necessary when FKB is written later. 
     What has been described above includes examples of the disclosed innovation. Furthermore, the term “region” or “information” include the same meaning of “area” or “data”, the term “secure storing medium” or “non-secure storing medium” can be described as “first storing medium” or “second storing medium”, the term “connected” includes the meaning of “electrically connected”, the term “contents” or “key” can be described as “content data” or “key data”, and the term “message” includes the meaning of “command”. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.