Abstract:
Provided is a data storing apparatus for recording data processed by a host system, and more particularly, to an authentication method of determining legality of the host system for accessing the data storing apparatus and recording medium storing the same. The authentication method includes: checking a connection elapsed time with the host system; when the connection elapsed time exceeds a predetermined time period, requesting the data storing apparatus to authenticate the host system; and determining to allow the host system to access the data storing apparatus according to the authentication result. According to the authentication method, the data storing apparatus counts the connection elapsed time with the host system, and authenticates the host system if the connection elapsed time exceeds a predetermined time period, thereby preventing the data storing apparatus from illegally being accessed by an authorized host system after the host system authenticates the data storing apparatus.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of Korean Patent Application No. 10-2004-0095892, filed on Nov. 22, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a data storing apparatus for recording data processed by a host system, and more particularly, to an authentication method for determining legality of a host system accessing the data storing apparatus and a recording medium storing the same.  
         [0004]     2. Description of the Related Art  
         [0005]     Examples of an image signal receiving apparatus provided with recording media for storing image signals include a settop box (STB) having a hard disk drive (HDD), a CD recording device or a DVD recording device, a personal video recorder (PVR), a monitor, a personal computer (PC), a VCR and the like.  
         [0006]     The STB is generally used for a video-on-demand (VOD) service. The VOD service is not a one-sided method in which data stream is transferred from a broadcast station to a user, but allows a user to directly select contents stored in a media database (MDB) to watch a favorite program at any time. The basic system for this VOD service includes a video source system provided with a video server, a subscriber&#39;s terminal such as an STB, and a network.  
         [0007]      FIG. 1  illustrates a configuration of a general VOD service. The VOD service is provided using an MDB  102 , a video server  104 , a basic communication network  106 , a subscriber network  108 , a STB  110 , and the like.  
         [0008]     The video server  104  performs the following functions: (1) receiving, processing and managing a user&#39;s request, (2) storing large amounts of digital video data, (3) multiple input/output, (4) database management, and (5) recovering faults.  
         [0009]     The STB  110  performs the following functions: (1) connecting a user to a subscriber network, (2) decompressing compressed video data, and (3) security and reservation. An STB for recording VOD service data is disclosed in Korean Patent Laid-Open Publication no. 1997-4852 (Jan. 29, 1997). In this publication, the STB can store VOD service data provided from a service provider on its HDD and allows a user to replay at anytime the VOD service data stored on the HDD after the communication with the service provider has finished.  
         [0010]      FIG. 2  illustrates an exemplary STB provided with a hard disc drive. In  FIG. 2 , the STB  200  comprises a system controller  204 , an interface  206 , an MPEG decoder  208 , a digital-to-analog converter (hereinafter, referred to as DAC)  210  and a HDD  212 . The system controller  204  controls the operation of the STB  200  of  FIG. 3  according to a user control command received through a remote controller receiver  202 . The interface  206  is connected to a video server  104  shown in  FIG. 1  under the control of the system controller  204 . The MPEG decoder  208  decodes the MPEG-compressed data transmitted from the video server  104  and restores video and audio data. The DAC  210  converts the restored video and audio data into an analog signal so as to output the converted analog signal through a TV set or a monitor. The HDD  212  stores the MPEG-compressed data transmitted from the video server  104 , or reproduces the stored MPEG-compressed data to provide the stored MPEG-compressed data to the MPEG decoder  208 .  
         [0011]     The apparatus shown in  FIG. 2  stores the VOD service data provided from the video server  104  on its HDD and allows the user to replay the VOD service data stored on the HDD after the communication with the video server  104  has finished.  
         [0012]     It is necessary to prevent data stored on the HDD of the STB from being illegally used, so that authentication is required between the HDD and the host system.  
         [0013]      FIG. 3  is a flowchart illustrating a conventional hard disk drive authentication method disclosed in Korean Paten Laid-Open Publication No. 1998-4630 (Mar. 30, 1998). In  FIG. 3 , when power is supplied to a host computer, a password input by a user is transmitted to a HDD. When the password is identical to a registered password, the HDD is changed into a normal mode, thereby allowing the host computer to perform a next operation. When the password is not identical to the registered password, and the number of new passwords inputted by the user exceeds an established number, the HDD is changed into an abnormal mode, thereby not allowing the host computer to perform the next operation.  
         [0014]      FIG. 4  is a block diagram of another conventional hard disk drive authentication method disclosed in Japanese Patent Laid-Open Publication No. 2004-70875 (Mar. 4, 2004). In  FIG. 4 , a secure system comprises an authentication server  1 , a plurality of user devices  2 , and a network  3  such as Internet. The plurality of user devices  2  comprise host computers  21  having a network-connected device, and hard disk drives  22  used as an external recording devices respectively.  
         [0015]     The authentication server  1  stores IDs of the hard disk drives  22  and IDs of the host computers  21 . When the host computers  21  access the hard disk drives  22 , the host computers  21  transmit ID authentication requests regarding the hard disk drives  22  and the host computers  21  to the authentication server  1 . The authentication server  1  performs authentication based on registered information, and transmits an authentication key to the host computers  21  after performing authentication successfully. The host computers  21  access hard disk drives  22  using the authentication key, and read data from the hard disk drives  22 .  
         [0016]     In the conventional hard disk drive authentication methods, the hard disk drive is authenticated when a host system is initially power-on or accesses the hard disk drive in order to prevent data stored on the hard disk drive from being accessed by an authorized user.  
         [0017]     However, after authentication is successfully performed, authentication is no longer required, or re-authentication is performed by the host system. That is, no authentication is performed by the hard disk drive.  
         [0018]     When the host system changes after authentication is performed by the host system, the hard disk drive is accessed by the changed host system.  
         [0019]     More specifically, even if the host system performs re-authentication of the hard disk drive after the host system and the hard disk drive authenticate each other, the hard disk drive does not perform re-authentication and thus the host system is not authenticated.  
         [0020]     Supposing that a cable for connecting the host system and the hard disk drive is separated from the host system and connected to another host system, since the hard disk drive re-authenticates another host system, the hard disk drive can be illegally accessed by another host system, i.e., an authorized host system.  
       SUMMARY OF THE INVENTION  
       [0021]     Accordingly, it is an aspect of the present invention to provide a method of authenticating a host system by a data storing apparatus connected to the host system.  
         [0022]     Another aspect of the present invention is achieved by providing a recording medium for storing a program suitable for the method.  
         [0023]     According to an aspect of the present invention, there is provided a method of authenticating a host system by a data storing apparatus accessed by the host system, the method including checking a connection elapsed time with the host system, requesting the data storing apparatus to authenticate the host system when the connection elapsed time exceeds a predetermined time period, and determining to allow the host system to access the data storing apparatus according to an authentication result.  
         [0024]     The checking of the connection elapsed time may include counting commands inputted by the host system and further counting a duration time while a command is not inputted by the host system.  
         [0025]     According to another aspect of the present invention, there is provided a computer readable recording medium storing a program of a method of authenticating a host system by a data storing apparatus accessed by the host system, the method including checking a connection elapsed time with the host system, requesting the data storing apparatus to authenticate the host system when the connection elapsed time exceeds a predetermined time period, and determining to allow the host system to access the data storing apparatus according to an authentication result.  
         [0026]     Another aspect of the present invention is achieved by providing an apparatus, including a host system to input commands via a host interface circuit, a command counter to count the inputted commands and an idle timer to count duration time while commands are not inputted, a controller to send an authentication result to the host system when the command counter exceeds a predetermined command limit or when the idle timer exceeds a predetermined time limit, and a disk drive to permit access to the host system according to the authentication result.  
         [0027]     Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]     These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
         [0029]      FIG. 1  illustrates a conventional configuration of a general VOD service;  
         [0030]      FIG. 2  illustrates a conventional settop box provided with a hard disc drive;  
         [0031]      FIG. 3  is a flowchart illustrating a conventional hard disk drive authentication method;  
         [0032]      FIG. 4  is a block diagram of another conventional hard disk drive authentication method;  
         [0033]      FIG. 5  is a flowchart of an authentication method according to the present invention;  
         [0034]      FIG. 6  is a block diagram illustrating an authentication performed between a host system and a hard disk drive via a serial interface;  
         [0035]      FIG. 7  is a block diagram of an authentication performed between the host system and the hard disk drive of  FIG. 6 , using a 20 th  pin of an integrated drive electronics (IDE) cable; and  
         [0036]      FIG. 8  is a diagram of a hard disk drive according to an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]     Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.  
         [0038]     A data storing apparatus according to the present invention may be a hard disk drive, a CD player, a DVD player, a PVR, and the like.  
         [0039]     According to an authentication method of the present invention, a data storing apparatus detects a connection elapsed time with a host system after completing a previous authentication. The connection elapsed time may be the number of commands inputted by the host system, an idle duration time, etc. When the connection elapsed time exceeds a predetermined time period, the data storing apparatus request the host system for authentication. When authentication is successfully completed, the host system is allowed to access the data storing apparatus. When the authentication is not successfully completed, the host system is not allowed to access the data storing apparatus.  
         [0040]      FIG. 5  is a flowchart of the authentication method according to the present invention. When the host system is turned on, authentication is performed between the host system and hard disk drive.  
         [0041]     In  FIG. 5 , the hard disk drive clears an idle timer and a command counter in Operation  502 . The idle timer is used to detect the idle duration time, and the command counter is used to count the number of commands inputted by the host system. The hard disk drive determines whether it is in an active mode in Operation  504 . If the hard disk drive is in an active mode, the hard disk drive increases the command counter by 1 whenever the host system inputs a command in Operation  506 . The hard disk drive checks whether a command counter value is more than a command limit in Operation  508 .  
         [0042]     If the command counter value is less than the command limit, the hard disk drive returns to Operation  504 . If the command counter value is more than the command limit, the hard disk drive performs authentication of the host system in Operation  510 .  
         [0043]     The hard disk drive determines whether the authentication is successfully performed in Operation  512 . If the hard disk drive successfully performs the authentication, the hard disk drive returns to Operation  502  and clears the idle timer and the command counter. If the hard disk drive fails to perform the authentication, the host system is not allowed to access the hard disk drive in Operation  514 .  
         [0044]     If the hard disk drive is in an inactive mode in Operation  504 , the hard disk drive performs in the idle mode, a standby mode, or a sleep mode in Operation  516 . The hard disk drive is established as one of the idle mode, the standby mode, or the sleep mode according to the inactive mode duration time.  
         [0045]     The hard disk drive increases the idle counter by 1 in Operation  518 . The hard disk drive checks whether an idle counter value is more than a time limit in Operation  520 . If the idle counter value is less than the time limit, the hard disk drive determines whether it is in the active mode in Operation  522 . If the hard disk drive is in the inactive mode, the hard disk drive returns to Operation  518 , and continues to count the inactive mode duration time. If the hard disk drive is in the active mode, the hard disk drive returns to Operation  506 , and the counts commands inputted by the host system. If the idle counter value is more than the time limit, the hard disk drive returns to Operation  510  and performs authentication of the host system.  
         [0046]     The hard disk drive authenticates the host system when the command counter or the idle timer exceeds the command limit or the time limit. The hard disk drive allows the host system to access it according to whether the authentication is successfully performed or not. If the host system is an authorized system, since the host system informs the hard disk drive of the successful authentication, and then, the host system is allowed to access the hard disk drive. If the host system is not an authorized system, the host system fails to inform the hard disk drive of the successful authentication, and the host system is not allowed to access the hard disk drive. After the authorized host system authenticates the hard disk drive, even if the hard disk drive is connected to another host system using a cable, another host system is unable to authenticate the hard disk drive, thereby preventing another host system from illegally accessing the hard disk drive and protecting data stored on the hard disk drive.  
         [0047]     When the hard disk drive transmits an authentication request signal to the host system, the host system transmits a signal in response to the authentication request signal, or authenticates an authentication key included in the hard disk drive and the host system.  
         [0048]      FIG. 6  is a block diagram of an authentication performed between the host system and the hard disk drive via a serial interface. When the command counter or the idle timer exceeds the command limit or the time limit, the hard disk drive  602  sends an authentication result to the host system  604  via the serial interface. The host system  604  is authenticated in response to the authentication request of the hard disk drive  602 , and transmits an authentication result to the hard disk drive  602  via the serial interface  606 . The hard disk drive  604  allows the host system  604  to access it according to the authentication result.  
         [0049]      FIG. 7  is a block diagram of an authentication performed between the host system and the hard disk drive of  FIG. 6 , using a 20 th  pin of an integrated drive electronics (IDE) cable. According to the AT Attachment Peripheral Interface (ATAPI) specification, the 20 th  pin of the IDE cable is not used to transmit a signal. The host system and the hard disk drive perform authentication by transmitting/receiving a predetermined signal using the 20 th  pin.  
         [0050]     When the command counter or the idle timer exceeds the command limit or the time limit, the hard disk drive  602  sends an authentication result to the host system  604  via the 20 th  pin. The host system  604  is authenticated in response to the authentication request of the hard disk drive  602 , and transmits an authentication result to the hard disk drive  602  using the 20 th  pin. The hard disk drive  604  allows the host system  604  to access it according to the authentication result.  
         [0051]      FIG. 8  is a diagram of the hard disk drive according to an embodiment of the present invention. In  FIG. 8 , the hard disk drive includes a controller  802  connected to a head  820  using a read/write (R/W) channel circuit  804  and a read preamp &amp; write driver circuit  806 . The controller  802  may be a digital signal processor (DSP), a microprocessor, a micro controller, etc.  
         [0052]     The controller  802  supplies a control signal to the R/W channel circuit  804  in order to read data from the hard disk drive  812  or write data to the hard disk drive  812 . The R/W channel circuit  804  transmits data to a host interface circuit  810 . The host interface circuit  810  includes a control circuit in order to interface a system such as a personal computer.  
         [0053]     The R/W channel circuit  804  modulates an analog signal read by the head  820  and amplified in the read preamp &amp; write driver circuit  806  into a digital signal read by the host computer (not shown), outputs the digital signal to the host interface circuit  810 , receives user data from the host computer via the host interface circuit  810 , converts user data into a write current written to the hard disk drive  812 , and outputs the write current to the read preamp &amp; write driver circuit  806  in a generation mode.  
         [0054]     The controller  802  is connected to a VCM operating circuit  808  for supplying an operating current to a voice coil  826 . The controller  802  supplies the control signal to the VCM operation circuit  808  in order to control VCM excitation and head motion.  
         [0055]     The controller  802  is connected to a nonvolatile memory such as a ROM  814  or a flash memory, and a RAM  816 . The ROM  814  and RAM  816  include commands and data used to execute a software routine by the controller  802 .  
         [0056]     One of the software routine is a program for executing the authentication method according to an embodiment of the present invention. The program is stored in the nonvolatile memory.  
         [0057]     The controller  802  counts commands inputted by the host computer via the host interface circuit  810  using the command counter, or counts a duration time while the command is not inputted using the idle timer.  
         [0058]     When the command counter or the idle timer exceeds the command limit or the time limit, the controller  802  sends an authentication result to the host system  604  using the serial interface or the 20 th  pin. The hard disk drive  602  allows the host system  604  to access it according to the authentication result. If the host system is an authorized system, the command counter or the idle timer is cleared, and the host system is allowed to access the hard disk drive  602 . If the host system  604  is not an authorized system, the host system  604  is not allowed to access the hard disk drive.  
         [0059]     The present invention may be carried out in the form of a method, a device or a system. When the present invention is carried out in the form of software, the elements of the present invention are essential code segments which perform necessary tasks. The program and code segments may be stored on a processor readable medium and transmitted in the form of a computer data signal coupled with a carrier wave in transmission media or communication network. The processor readable medium may be any medium through which information can be stored or transmitted. Examples of the processor readable medium include electronic circuit, semiconductor memory device, read-only memory (ROM), flash memory, erasable ROM (EROM), floppy disks, optical data storage devices, hard disks, optical fiber medium, radio frequency network, and the like. The computer data signal may be any signal that can be transmitted through transmission medium such as electronic network channel, optical fiber, air, electromagnetic field, radio frequency network, and the like.  
         [0060]     According to the authentication method of the present invention, a data storing apparatus counts a connection elapsed time with a host system, and authenticates the host system if the connection elapsed time exceeds a predetermined time period, thereby preventing the data storing apparatus from illegally being accessed by an authorized host system after the host system authenticates the data storing apparatus.  
         [0061]     Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.