Abstract:
To protect a password from leakage, it is necessary to change it frequently, which is troublesome and difficult to be done realistically. According to the present invention, an encrypted access code is stored in a transportable and nonvolatile memory on the part of a computer to be remotely accessed. When a user actually carries the nonvolatile memory to plug it into a computer remotely accessing, remote access is established between the computer to be remotely accessed and the computer remotely accessing.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a remote access system in a network using radio transmission, a remote access method, and a medium containing a remote access program 
   2. Description of the Related Art 
   In recent years, computers at remote sites have been accessed over networks. Because a computer is connected to a network, it is necessary to discourage unauthorized persons from accessing the computer. Conventionally, an access code (a password) is registered in advance with a remote computer. When the access code is inputted through a computer to be operated, the access code is sent to the remote computer, which determines whether or not to allow the access. 
   The disadvantage of a password is that it can leak out. A password as information that a person can memorize may leak out. Once it leaks out, unauthorized access can easily be made. 
   In order to prevent the risk of leakage, it is necessary to change the password frequently. However, it is troublesome and difficult to be done realistically. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a remote access system comprising a pair of computers in which one computer is connected with another computer through a network organized by way of radio transmission, and its primary feature is as follows: 
   An access code for allowing remote access is registered with the above one computer. Also, a transportable and removable nonvolatile memory can be plugged into the above computer, which encrypts the above access code by a prescribed method and stores it in the nonvolatile memory. The other computer can accommodate the above nonvolatile memory. Further, when the nonvolatile memory is plugged into it, the computer can decrypt the encrypted access code and makes it possible to access the above one computer by using the decrypted access code. 
   A user achieves remote access by using a pair of computers connected by way of radio transmission. On this occasion, an access code is registered with one computer. The access code may be the one peculiar to the computer, or the user may set it himself or herself. A nonvolatile memory is plugged into the computer, and the above access code is encrypted by a method of some kind and stored. At this point, the nonvolatile memory becomes a physical key. The user takes this physical key to the other computer and plugs it into the computer. Then, the user decrypts the access code encrypted and stored in the nonvolatile memory and gains access to the other computer through a network by using the access code. 
   Thus, on the side accessed from a remote site, the access code registered with the computer is encrypted and stored in the physical nonvolatile memory. When accessing from the remote site, a holder of the nonvolatile memory plugs it into the computer and decrypts the access code. Therefore, the access code is prevented from leaking out and the remote access system which improves security by a simple method can be achieved. 
   According to one of the embodiments of the invention, the above nonvolatile memory may be a SmartMedia card. Also, it may be a USB memory. 
   As an example where such remote access is applied, it may be the case in which the above one computer is installed in a motor vehicle. If a computer is installed in the motor vehicle, it becomes possible to remotely access the computer in the motor vehicle, in a garage of each home, from a desktop computer at home within a range of a wireless LAN of a home network. By connecting the computer with an engine system, a security system, and a navigation system of the motor vehicle, usefulness in many ways can be enhanced. 
   Each motor vehicle has its own vehicle identification number. Therefore, as in the invention according to claim  5 , the vehicle identification number may be included in the access code. Thus, diversity and uniqueness of the access code are enhanced, contributing to the improvement of security and, when the motor vehicle is stolen, to the discovery of the vehicle by using the vehicle identification number. As one aspect where a vehicle identification number is included in the access code, being based on the vehicle identification number itself, a password designated by a user may be added. Also, as far as the discovery of the vehicle in the case of theft is concerned, it may be such a system that a response is obtained by using the vehicle identification number only in specific circumstances. 
   Further, as an example of the case of the other computer, according to one of the embodiments of the invention, the access code of the other computer may be based on an individual identification number of its CPU. In this case also, while being based on the individual identification number only, an access code with a user&#39;s password added may be generated. In the case of the other computer installed at home, according to one of the embodiments of the invention, the other computer may be a home server storing music data. In this regard, if one computer is installed in a motor vehicle, it becomes possible for a user to have the computer in the vehicle download the user&#39;s music files and to reproduce them on a car audio system when the user drives the car next time. 
   It serves the purpose if radio transmission is at least partially involved in the network. According to one of the embodiments of the invention, the pair of computers described above may be connected with each other in a home network system. Alternatively, according to one of the embodiments of the invention, the pair of computers may be connected with each other through the Internet. 
   It is difficult to change the password frequently in that we depend on our memory. However, according to one of the embodiments of the invention, when the nonvolatile memory described above is removed, the above access code may be generated at random and stored in the other computer as well as in the nonvolatile memory. Namely, the nonvolatile memory is loaded when the above one computer is being used by a user himself or herself and, if the nonvolatile memory is removed after the operation, a new access code is generated at random. When the user leaves the one computer and moves to a site where the other computer is located, the nonvolatile memory is plugged into the other computer. Since the access code is generated during the most recent operation, the risk of remote access being made by an outsider in the mean time can be minimized. In particular, when the user leaves one place for another, the access code is generated at the end of the operation of the computer to be remotely accessed, and the computer is located at a site where it is actually inoperable, which would be convenient. 
   Since the access code is a piece of information, unauthorized access can be made if it leaks out. Encryption is used to prevent it and to cope with a case where a nonvolatile memory is stolen. However, as an example to further improve security, according to one of the embodiments of the invention, first key data, which are like a pair of a public key and a secret key, are each stored in the above pair of computers. The data encrypted by using one key data cannot be decrypted without using the other key data. Accordingly, on the part of the one computer, the above access code is encrypted by the one key data and stored in the nonvolatile memory. This way, even if the nonvolatile memory is obtained in an unauthorized manner, it is almost impossible to decrypt the access code in it. Further, even when the nonvolatile memory is left behind, it is often the case that the nonvolatile memory and the pair of computers are in different locations, and decryption of the access code is meaningless. 
   In order to access remotely, the nonvolatile memory is plugged into the other computer. Then, the access code can easily be decrypted by using the other key data stored in the computer, and the remote access becomes available by using it. 
   Further, the system may be configured such that, when leaving the computer, the key data is used to password-lock the computer so as to respond only to the remote access and, accordingly, the lock cannot be released without the nonvolatile memory, which can improve security. 
   Even if the nonvolatile memory is not stolen, the access code in it may leak while being transmitted over a network. According to one of the embodiments of the invention, when the other computer remotely accesses the one computer, it uses the above other key data to encrypt the access code and transmits it. The above one computer decrypts the encrypted access code by using the above one key data, compares the pre-stored access code with the access code transmitted and authenticates it. Therefore, even when information is obtained on a network, an unauthorized use of it is impossible without the pair of key data. 
   Of course, it is obvious that the invention is also realized in individual computers making up such a remote access system. 
   According to the above method, as the user moves, the access code is stored in the transportable and physical nonvolatile memory and remote access is made from a new location of the user to the computer that the user left. Application of this method is not limited to a substantial apparatus, and it is easily understood that it functions as a method itself. Thus, a remote access method in a network system in which a pair of computers each capable of accommodating a transportable and removable nonvolatile memory are connected at least by way of radio transmission is available. An access code for allowing remote access is registered with one computer, and the access code is encrypted in a prescribed manner and stored in the nonvolatile memory. The other computer decrypts the above encrypted access code when the nonvolatile memory is plugged into it and becomes capable of accessing the above one computer by using the decrypted access code. Namely, application of this method is not limited to a substantial apparatus, and the invention is effective as a method itself. 
   Incidentally, such a remote access system may exist alone or it may be incorporated into a certain apparatus, and the spirit of the invention includes various kinds of aspects. Therefore, it may be software or hardware according to the need. 
   As an embodiment of the spirit of the invention, when the remote access system is software, it naturally exists in a storage medium containing such software and is utilized. 
   As an example, a medium which contains a remote access program for a network system wherein a pair of computers each capable of accommodating a transportable and removable nonvolatile memory are connected at least by way of radio transmission is available. An access code for allowing remote access is registered with one computer, and a function of encrypting the access code by a prescribed method and storing it in the nonvolatile memory is achieved. At the other computer, a function of decrypting the encrypted access code when the nonvolatile memory is plugged into it and accessing the above one computer by using the decrypted access code is achieved. 
   Of course, the storage medium may be a magnetic storage medium or a magneto optical storage medium, or it may be any storage medium to be developed in the future. Further, stages of reproduction such as a first reproduction and a second reproduction are doubtlessly equivalent. Further, the present invention is also doubtlessly utilized even when a communication line is used as a supplying means. 
   Further, the spirit of the invention is still the same even if it is partly software and partly hardware, or it may be in a form where a part of it is stored in a storage medium and is read out as the need arises. 
   When achieving the present invention in the form of software, it is possible to utilize hardware or an operating system. Alternatively, it can be achieved separately from them. In the case of computing, for example, it can be achieved by calling up a prescribed function in the operating system and carrying out processing. Alternatively, data entry can be made by using hardware without calling up such a function. Even if it is achieved actually through the operating system, it is understood that the present invention can be realized by this program alone in a process where the program is stored on the medium and transferred. 
   Further, when achieving the present invention with software, it is a matter of course that not only the invention is embodied as a medium containing a program but also the invention is embodied as a program itself, and the program itself is included in the present invention. 
   According to the present invention, on the part of the computer accessed from a remote site, the access code registered with the computer is encrypted and stored in a physical nonvolatile memory. When accessing from the remote site, a holder of the nonvolatile memory plugs it into the computer and decrypts the access code. Accordingly, the access code does not easily leak, achieving a remote access system in which security is improved with a simple method. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic diagram of a network system to which the present invention is applied (Embodiment 1); 
       FIG. 2  is a block diagram showing a configuration of each computer in the network system; 
       FIG. 3  is a schematic diagram showing encryption and decryption of an access code in a remote access system; 
       FIG. 4  is a flowchart showing a process performed by each computer; 
       FIG. 5  is a flowchart showing a process performed by each computer; 
       FIG. 6  is a flowchart showing a process performed by each computer; 
       FIG. 7  is a schematic diagram showing an authentication method in a remote access system of another embodiment; 
       FIG. 8  is a flowchart showing a process performed by a home server PC; and 
       FIG. 9  is a flowchart showing a process performed by a vehicle-mounted computer. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the drawings, embodiments of the present invention will now be described. 
   [Embodiment 1] 
     FIG. 1  is a schematic diagram of a network system to which the present invention is applied. 
   In  FIG. 1 , a local area network (hereafter called LAN)  10  is compatible with both the wire system and wireless system. A desktop computer (hereafter called home server PC)  20  has a function of a home server and is connected to the LAN  10  through the wire system. A vehicle-mounted computer  30  is installed in a motor vehicle and is connected to the LAN  10  by the wireless system. 
     FIG. 2  is a detailed block diagram of the network system. Connected to the home server PC  20  are a CPU  22 , ROM  23 , RAM  24 , and the like through a bus  21 . Also, a hard disk  25  storing programs and data, as well as a keyboard  26   a , a mouse  26   b , and a CRT  27  through a prescribed interface is connected to the home server PC  20 . 
   Further, the home server PC  20  has a USB interface  28  with which various USB-compliant devices can be connected. As one of the USB-compliant devices, a USB memory  40  to be described later can be connected to the home server PC  20 , which is capable of writing and reading data to and from the USB memory  40  by executing a prescribed program. 
   Further, the home server PC  20  has a wired LAN interface  29 , and is connected to the LAN  10  through the wired LAN interface  29 . 
   The vehicle-mounted computer  30  also has a configuration basically similar to the home server PC  20 . A CPU  32 , ROM  33 , RAM  34 , and the like are connected to the computer  30  through a bus  31 . Also, a hard disk  35  storing a program and data, as well as an operating panel  36 , a display  37 , etc. through a prescribed interface. Further, the vehicle-mounted computer  30  has a USB interface  38  through which the USB memory  40  is connected so that data are written and read to and from it, and also has a wireless LAN interface  39  for connection to the LAN  10 . 
     FIG. 3  shows a process in outline of encryption and decryption of the access code.  FIGS. 4 through 7  show flowcharts for achieving remote access by using the encryption and decryption. 
   As a prerequisite to it, an uncorrectable unique ID is stored in the home server PC  20  and an uncorrectable vehicle identification number VIN is stored in the vehicle-mounted computer  30 . Also, what we call a public key PUB and a secret key SEC are stored. The public key PUB and the secret key SEC are key data which are used in a pair. Namely, data encrypted by one of the key data cannot be decrypted unless the other of the key data is used. The vehicle identification number VIN, which is an access code of the vehicle-mounted computer  30  is encrypted by using the public key PUB, stored in the USB memory  40 , and decrypted on the part of the home server PC  20  by using the secret key SEC. The decrypted vehicle identification number VIN is encrypted by the secret key SEC and is sent to the vehicle-mounted computer  30  over the LAN  10 . The vehicle identification number VIN of the vehicle-mounted computer  30  is decrypted by using the public key PUB and is used for authentication. Also, the unique ID is subjected to the same processing. In either case, every time the encryption is conducted the different data is added so that the data itself after the encryption may change. 
     FIGS. 4 and 5  show flowcharts of programs executed by the CPU  32  of the vehicle-mounted computer  30  to be remotely accessed and the CPU  22  of the home server PC  20 . The programs are recorded on hard disks  35  and  25 . 
   An example for achieving remote access from the home server PC  20  to the vehicle-mounted computer  30  will be described below. 
   At the vehicle-mounted computer  30 , when the USB memory  40  is attached to the USB interface  38 , the access code is stored in the USB memory  40  as shown in the flowchart of  FIG. 4 . As a prerequisite to it, a name and so on to be a flag as a medium storing the access code is given to the USB memory  40  by a utility program (not shown), etc. 
   In step S 100 , the access code is encrypted by the public key PUB/secret key SEC, and the encrypted data is written into the USB memory  40  in step S 110 . For the access code, any one of the vehicle identification number VIN, the unique ID, random data RND produced by the random numbers every time the program is started, and the user&#39;s password UPW set by the user in advance, or a combination thereof may be used. Further, whether to use the public key PUB or the secret key SEC depends on which of the vehicle-mounted computer  30  and the home server PC  20  is used. The vehicle-mounted computer  30  uses the public key PUB and the home server PC  20  uses the secret key SEC. On the program, the key data stored in an area of each computer may be used, and there is no need to differentiate between the public key PUB and the secret key SEC. 
   The vehicle identification number VIN is useful for finding the stolen vehicle in that every vehicle-mounted computer  30  has a different number without exception. As for the random data RND, every time the USB memory  40  is plugged in, discrete data is always created. Therefore, it has an advantage in that less devices have leakage of data and in that the same data is not used over a long period. The user&#39;s password UPW has an advantage in accomplishing security in that it can further be set for every user even when generating algorithm of the random data or when the vehicle identification number VIN leaks out. Depending on the case, it is also useful as a user code for specifying each of the plurality of vehicle-mounted computers  30  owned by the user. In the case of the home server PC  20 , an ID and so on stored in its CPU are used instead of the vehicle identification number VIN. 
   When using random data RND or the user&#39;s password UPW, in step S 120 , it is stored on the hard disk  35  which is a nonvolatile storage area. Further, it is preferable to encrypt the hard disk  35  itself by a conventional encryption technology. 
   After storing the access code in the USB memory  40  like this, the vehicle-mounted computer  30  authenticates a request for remote access inputted through the LAN  10 .  FIG. 5  is a flowchart of the authentication of the remote access. 
   In step S 150 , an encrypted access code is obtained through the LAN  10 . 
   In step S 160 , by using the public key PUB/secret key SEC stored in the vehicle-mounted computer  30 , the encrypted access code is decrypted. In step S 170 , it is determined whether or not the decrypted access code matches the stored access code. If it does, the remote access is successfully authenticated and the access thereafter is allowed. In this case, also, it serves the purpose if the vehicle-mounted computer  30  uses the public key PUB and the home server PC  20  uses the secret key SEC and, on the program, each computer uses key data stored in an area of itself. Therefore, there is no need to differentiate between the public key PUB and the secret key SEC. 
   Above example is the case when achieving remote access from the home server PC  20  to the vehicle-mounted computer  30 . On the contrary, if it is the case when achieving remote access from the vehicle-mounted computer  30  to the home server PC  20 , the home server PC  20  performs the above processing to encrypt the access code and store it in the USB memory  40 , or to conduct authorization on the basis of the inputted access code through the LAN  10 . 
     FIG. 6  is a flowchart of the program executed by the CPU  32  of the vehicle-mounted computer  30  making remote access and the CPU  22  of the home server PC  20 , and the programs are stored on the hard disks  35  and  25 . 
   When the USB memory is plugged into the computer in step S 200 , the encrypted and stored data is read and is decrypted by using the public key PUB/secret key SEC. In this case, also, the vehicle-mounted computer  30  uses the public key PUB and the home server PC  20  uses the secret key SEC. The decrypted access code can be any one of a vehicle identification number VIN, a unique ID, random data RND produced by using random numbers every time the program is started, and a user&#39;s password UPW set in advance by the user, or a combination thereof. Since the access code is sent to the side which generated it and is authenticated, it is needless to judged the contents thereof. 
   In step S 210 , the decrypted access code is encrypted this time by using the computer&#39;s own public key PUB/secret key SEC. Then, in step S 220 , a request for remote access is outputted to a computer which is trying to access remotely through the LAN  10 , and the above encrypted access code is sent out on that occasion. The request for the remote access is made by a conventional method, and the access code is sent out when the password and so on are requested. In the decryption process (step S 160 ), the access code sent out this way is, according to the flowchart shown in  FIG. 5 , decrypted by the public key PUB/secret key SEC of the other party and is used for authentication (step S 170 ). If the authentication is successful, requests for access to be made thereafter are automatically allowed. 
   Now, workings of the present embodiment configured as above will be described. 
   Let us suppose that the vehicle-mounted computer  30  is a part of the car audio system. In such a case, a user can gain access to the home server PC  20  from the vehicle-mounted computer  30  in the garage, read a music file stored in the home server PC  20 , and store it on the hard disk  35 . Alternatively, the user can remotely access the vehicle-mounted computer  30  in the garage, send out the music file from the home server PC  20 , and stores it on the hard disk  35 . 
   In order to send the music file from the home server PC  20 , it is necessary to bring the access code of the vehicle-mounted computer  30  to the side of the home server PC  20 . Therefore, when having parked the car, the user attaches the USB memory  40  to the USB interface  38  of the vehicle-mounted computer  30 . Then, through the steps S 100 - 120 , the access code is encrypted by using the public key PUB in the vehicle-mounted computer  30  and is stored in the USB memory  40 . With this regard, a process of generating random data RND by setting and including it in the access code is also performed. 
   The user removes the USB memory  40  and plugs it into the home server PC  20  at home. Then, in step S 200 , the encrypted access code is read from the USB memory and is decrypted by using the secret key SEC. In step S 210 , the access code is encrypted by the secret key SEC and, while using the encrypted access code, in step S 220 , a request for remote access is made. 
   Since the vehicle-mounted computer  30  is connected to the LAN  10  through a wireless LAN, it conducts authentication upon receipt of a request for remote access. In this regard, in step S 150 , an access code is requested like a password is requested, and the inputted access code is decrypted in step S 160  by using the public key PUB. In step S 170 , it is judged whether the decrypted access code matches the stored access code for authentication. 
   When the authentication is conducted, by a conventional remote access method, the music file is transferred from the hard disk  25  to the hard disk  35 . 
   Of course, it is possible to plug the USB memory  40  into the home server PC  20  before leaving home, generate the access code for the home server PC  20 , store it in the USB memory  40 , and take it out. Then, by plugging the USB memory  40  into the vehicle-mounted computer  30 , a request for remote access is sent from the vehicle-mounted computer  30  to the home server PC  20 , the music file stored on the hard disk  25  of the home server PC  20  is read remotely, and is written onto the hard disk  35  of the vehicle-mounted computer  30 . 
   [Embodiment 2] 
   In the above example, the USB memory is used as a transportable storage medium for the access code. However, it serves the purpose so long as it is a transportable storage medium, and a SmartMedia card, etc. may be used. Further, the remote access may be achieved within an existing security environment, and such restriction may be added that a certain user may read but cannot write or delete data. 
   [Embodiment 3] 
   In the above example, in addition to the encryption of the access code written into the USB memory  40 , the encryption is used during the transmission of the access code over the LAN  10 . However the latter may be adopted as an option. 
   [Embodiment 4] 
   In the above example, the remote access is achieved between the vehicle-mounted computer  30  and the home server PC  20  by using the LAN  10 . However, a router may be provided on the LAN  10  for connection to the Internet. In this way, when the vehicle-mounted computer  30  enters a hot spot in a service area of a highway, etc., the connection to the home server PC  20  through the Internet and the LAN  10  becomes possible. In this regard, if the USB memory  40  in which the access code is stored by the home server PC  20  in advance is plugged into the vehicle-mounted computer  30 , the safe remote access can be achieved by using the security described above. 
   [Embodiment 5] 
   In the above examples, writable storage media such as the USB memory  40 , etc. are used. However, if a vehicle in which the vehicle-mounted computer  30  is installed is an immobilizer-compatible vehicle, the following are also possible. 
   A key  50  of an immobilizer is provided with an electronic chip called a transponder. An ID code of the electronic chip is read by an ignition switch. Unless the ID code of the chip matches an ID code registered with an electronic control unit in the vehicle, an engine is not started electrically. 
   In the present embodiment, the home server PC  20  is provided with a receiving unit  60  for reading the ID code of the key  50 , and the receiving unit  60  is connected with the bus  21  through a receiving unit I/F  61 . 
   If a user has put the vehicle into a garage and returned home, and wishes to access the vehicle-mounted computer  30 , first, the user places the key  50  beside the receiving unit  60 , and reads the ID code of the key  50  by using a driver (not shown) of the receiving unit I/F  61  (step S 310 ). The ID code read out is stored in a nonvolatile memory such as the hard disk  25  (step S 320 ). Then, while encrypting the ID code by the prescribed encryption technology, the user accesses the vehicle-mounted computer  30  through the LAN  10  and wireless LAN, and sends the ID code as a code for authentication (step S 330 ). 
   Upon receipt of a request for authentication (step S 400 ), the vehicle-mounted computer  30  decrypts the ID code encrypted and sent, and compares the decrypted ID code with the ID code registered with the electronic control unit in the vehicle (step S 460 ). When both codes are compared (step S 470 ) and if they match with each other, the authentication is successful (step S 480 ). If not, the authentication is not successful (step S 490 ). 
   On the part of the home server PC  20 , when the ID codes match with each other as described above, the authentication is completed (step S 340 ), and the access thereafter (step S 350 ) is made. 
   On the other hand, when the user gains access to the home server PC  20  at home from the vehicle-mounted computer  30  in the vehicle, as described above, a process is performed once so that the home server PC  20  can access the vehicle-mounted computer  30 . Accordingly, the ID code is stored on the hard disk  25 , which is a nonvolatile memory, of the home server PC  20 . 
   On the part of the vehicle-mounted computer  30 , first, the ID code registered with the electronic control unit in the vehicle is read out (step S 410 ). While the read out ID code is being encrypted by the same encryption technology as above, access is made to the home server PC  20  through the wireless LAN and the LAN  10 , and the ID code is sent as a code for authentication (step S 420 ). 
   On the part of the home server PC  20 , when receiving a request for authentication (step S 300 ), the ID code encrypted and sent is decrypted, and the decrypted ID code is compared with the ID code stored on the hard disk  25  (step S 360 ). When both are compared (step S 370 ), and if the former matches the latter, the authentication is successful (step S 380 ). If not, the authentication is not successful (step S 390 ). 
   On the part of the vehicle-mounted computer  30 , if the ID codes match with each other as above, the authentication is completed (step S 430 ), and the access thereafter (step S 440 ) is made. 
   Further, there is also an immobilizer in which the ID code is changed every time the key  50  is inserted or removed. In such a case, authentication is conducted according to the latest ID code, ensuring higher levels of security. 
   To sum up, it is a remote network system wherein one computer installed in a motor vehicle which adopts a security system using an immobilizer having an ID code is connected with the other computer at least by way of radio transmission. 
   The other computer is capable of obtaining the ID code of the immobilizer and is capable of sending the obtained ID code through the network to the above one computer to ask for authentication. 
   Further, when receiving the ID code and the request for authentication from the one computer through the network, it is also capable of comparing the ID code with the above ID code obtained in advance and conducting authorization. 
   The above one computer is capable of comparing the ID code sent from the other computer through the network with the ID code registered with the above vehicle and authenticating it, and is also capable of sending the ID code registered with the vehicle in advance through the network to the other computer and requesting authentication. 
   Of course, as an invention, there is no doubt that it is also achieved in individual computers making up such a remote access system. 
   An encrypted access code is stored in a transportable and nonvolatile memory on the part of the computer to be remotely accessed, and a user in person carries the nonvolatile memory and plugs it into the computer remotely accessing, which allows the remote access between the computer to be remotely accessed and the computer remotely accessing.