JPH11265318A - Mutual certification system, its method and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide mutual certification device and method capable of certifying a person intending to access to data stored in a detachable storage device. SOLUTION: An access device 2 prepares a user key and a certification password from a password supplied from a user. Then the device 2 prepares a delivery key, ciphers a user key by the delivery key and supplies the ciphered user key to a memory card 1 to deliver the memory card 1 from the device 2 to the card 1. The card 1 deciphers the user key, decipers a card key by using the user key and a system key and deciphers the ciphered certification password by using the card key. Then each of the card 1 and the device 2 prepares two digests for the certification password deciphered or prepared by itself, exchages one of the two digests with the opposite, compares the digest prepared by itself with the digest obtained from the opposite, and when both the digests are substantially identical, permits a user's access.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mutual authentication system and a mutual authentication method, and more particularly to a mutual authentication system and a mutual authentication method for protecting stored data from unauthorized access.

[0002]

2. Description of the Related Art In recent years, a flash memory card which has a PCMCIA interface or the like as an external storage device and is detachably connected to a personal computer main body has been used in a notebook personal computer or the like.

[0003]

However, the data stored in the flash memory card can be withdrawn from the personal computer main body by connecting the flash memory card to another computer or the like. It was easy to read. For this reason, flash memory cards are not suitable for storing confidential data.

The present invention has been made in view of the above circumstances, and provides a mutual authentication system and a mutual authentication method capable of authenticating a person who accesses data stored in a removable storage device. With the goal.

[0005]

In order to achieve the above object, a mutual authentication system according to a first aspect of the present invention comprises storage means and access means, wherein the access means is operated by an operator. Means for creating first authentication data based on the password supplied by the first means, means for creating a delivery key and supplying it to the storage means, and the first authentication data cannot be substantially reverse-converted. A first digest creating means for creating a first digest representing a converted version of the first authentication data; and a second digest representing a converted version of the first authentication data so that the first authentication data cannot be substantially converted. , A second digest creating means for supplying to the storage means, wherein the storage means has a storage area for storing data, and an encrypted second And means for storing proof data,
Means for decrypting the encrypted second authentication data using a delivery key supplied from the access means;
Third digest creating means for creating a third digest representing a result obtained by converting the second authentication data so that the inverse conversion cannot be substantially performed, and supplying the third digest to the access means; and A fourth digest creating means for creating a fourth digest representing a result of transforming the second digest so that the inverse transformation cannot be performed substantially, and obtaining the second digest from the access means, It is determined whether the digest of No. 4 indicates substantially the same authentication data, and when it is determined to indicate, the data supplied from the access means is stored in the storage area in accordance with the instruction of the access means. Means for storing, obtaining the data from the storage area, and supplying the data obtained from the storage area to the access means. Access means obtains the third digest from the storage means, determines whether or not the first and third digests indicate substantially the same authentication data, and determines that the authentication data indicates the authentication data. An instruction for requesting the storage unit to acquire the data from the storage area, an instruction for requesting storage of the data in the storage area, and a unit for supplying the data to the storage unit. It is characterized by the following.

According to such a mutual authentication system, the storage means and the access means are such that the authentication data stored in the storage means and the authentication data generated from the password supplied to the access means are substantially the same. Then, the user or the like is permitted to access the storage area of the data storage means. Therefore, if the password is not disclosed to anyone other than the user, the person who accesses the data is authenticated.

The access means creates a user key based on the password, encrypts the user key using the delivery key to create an encrypted user key, and stores the encrypted user key in the storage means. The storage means has a storage area substantially inaccessible from the access means, in the storage area,
Means for storing a system key, the encrypted second authentication data and an encrypted unique key, and means for decrypting the encrypted user key supplied from the access means using the delivery key And a unique key decrypting means for decrypting the encrypted unique key using the system key and the decrypted user key; and decrypting the encrypted first authentication data. Authentication data decrypting means for decrypting using the unique key and creating the second authentication data. This increases the secrecy of the second authentication data,
Further, the confidentiality of the data used for decrypting the second authentication data is increased, and the risk that access to the storage unit is erroneously permitted due to an unauthorized operation or the like is reduced.

The storage means, when the access means issues the instruction requesting storage of the data in the storage area and supplies the data to be stored in the storage area, Means for encrypting the decrypted data using the decrypted unique key and storing the encrypted data in the storage area, and wherein the access means requests acquisition of the data stored in the storage area. Means for obtaining the encrypted data from the storage area when receiving the instruction, decrypting the data using the decrypted unique key, and supplying the decrypted data to the access means. Is also good. As a result, the data stored in the storage area of the data storage means is stored in a state of being encrypted with the unique key. For this reason, even if the storage area receives an unauthorized access, the contents of the data will not be leaked unless the person who has made the unauthorized access knows the unique key. Therefore, the confidentiality of the data is further enhanced.

[0009] The unique key decryption means substantially prevents the data generated for decrypting the encrypted unique key and the decrypted unique key from being supplied to the access means. The authentication data decrypting means may include means for decrypting the encrypted first authentication data and data generated for decrypting the encrypted first authentication data. There may be provided a means for substantially preventing the supply to the access means. Thereby, the data generated in the process of restoring the unique key and the authentication data is also concealed, so that the data leaks to the outside and the danger that the unique key and the authentication data are back calculated is reduced.

[0010] The access means acquires first delivery key information from the storage means and means for generating a first random number, and acquires the first delivery key information based on the first delivery key information and the first random number. Means for creating the delivery key, and a second random number from the storage means, and creates second delivery key information based on the second random number and the first random number. Means for supplying delivery key information to the storage means, wherein the storage means generates the second random number and the third random number, and stores the second random number and the third random number based on the second and third random numbers. A means for generating the first delivery key information and supplying the first delivery key information and the second random number to the access means; and the third delivery means provided by the third random number and the access means. Substantially the same as the first delivery key based on the key information Means for creating a second of the delivery key, may be provided with a. As a result, the delivery key is also sent from the access means to the storage means while maintaining the confidentiality. Therefore, the delivery key is illegally acquired, and the data exchanged between the access means and the storage means is decrypted illegally. Dangers such as

In the first to fourth digests, for example, the access unit includes a unit that generates a fourth random number and supplies the generated random number to the storage unit, and the first digest creation unit includes the first digest. Means for generating the first digest by obtaining a value of a one-way function using the authentication data of the first and the fourth random numbers as variables, and
The digest creation means of the first authentication data,
Means for generating the second digest by obtaining a value of a one-way function having the third random number as a variable, wherein the third digest generating means includes: the second authentication data; Means for generating the third digest by obtaining a value of a one-way function having a fourth random number as a variable, wherein the fourth digest generating means includes: the second authentication data; The fourth digest is generated by obtaining a value of a one-way function having three random numbers as variables.

[0012] The access means may include identification information for identifying the operator, supplied in accordance with the operation of the operator.
Means for generating signature information for identifying the operator by performing conversion so that inverse conversion cannot be performed substantially, and for supplying the signature information to the storage means, wherein the storage means is supplied from the access means. Means for obtaining said signature information,
It is determined whether or not the signature information is stored in the storage area, and when it is determined that the signature information is not stored, the signature information supplied from the access unit is stored in the storage area and stored. It is determined whether the stored signature information and the signature information supplied from the access unit indicate substantially the same operator, and it is determined that the signature information does not indicate the same operator. Means for refusing to comply with the instruction given by the access means when the access is made. Accordingly, when a person who has already accessed the storage area of the data storage means is substantially prevented from accessing the storage area by another person, the data in the storage area is stored by another person. The risk of being acquired is reduced.

Further, a mutual authentication system according to a second aspect of the present invention comprises: a storage unit having a storage area for storing data; and an access unit having a unit for accessing the storage area. The access means converts the identification information, which is supplied according to the operation of the operator, for identifying the operator so that the inverse conversion cannot be substantially performed, creates signature information for identifying the operator, and generates the signature information. Means for supplying information to the storage means, wherein the storage means obtains the signature information supplied from the access means, and determines whether or not the signature information is stored in the storage area. When it is determined that the signature information is not stored, the signature information supplied from the access unit is stored in the storage area, and when it is determined that the signature information is stored, the signature information is stored. It is determined whether the signature information provided by the access unit and the signature information supplied by the access unit indicate substantially the same operator. Means for refusing to follow the instruction.

According to such a mutual authentication system, when a person who has already accessed the storage area of the data storage means is substantially prevented from accessing the storage area by any other person, The danger that data in the storage area is obtained by another person is reduced.

The present invention is particularly suitable when the storage means is detachably connected to the access means.

Further, a mutual authentication method according to a third aspect of the present invention comprises a storage step and an access step, wherein the access step is based on a password supplied by an operation of an operator. A step of creating authentication data, a step of creating a delivery key and supplying it to the storage step, and a first digest representing the first authentication data converted so as not to be substantially inversely converted. And a second digest representing the first authentication data converted so that the reverse conversion cannot be performed substantially, and the second digest supplied to the storage step. A digest creation step, wherein the storage step includes a data storage step including a storage area for storing data; Storing the obtained second authentication data, decrypting the encrypted second authentication data using the delivery key supplied from the access step, and substantially storing the second authentication data. Creating a third digest representing what has been converted so that it cannot be inversely converted, and supplying a third digest to the access step; and performing a substantially inverse conversion of the second authentication data. A fourth digest creation step of creating a fourth digest representing the result of the conversion, and obtaining the second digest from the access step, wherein the second and fourth digests are substantially the same. Determine whether or not to indicate the authentication data of,
When determined to indicate, according to the instruction of the access step, storage of the data supplied from the access step in the storage area, acquisition of the data from the storage area, and the data acquired from the storage area Providing to the access step of
The access step obtains the third digest from the storage step, determines whether the first and third digests indicate substantially the same authentication data, and indicates When it is determined, the instruction to request the storage step to acquire the data from the storage area, the instruction to request the storage of the data in the storage area, and the supply of the data to the storage step are performed. It is characterized by comprising a step.

According to such a mutual authentication method, the storing step and the accessing step are such that the authentication data stored in the storing step and the authentication data created from the password supplied to the accessing step are substantially the same. Then, the user or the like is permitted to access the storage area in the data storage step. Therefore, if the password is not disclosed to anyone other than the user, the person who accesses the data is authenticated.

According to a fourth aspect of the present invention, there is provided a computer readable recording medium comprising: a data storage unit having a storage area for storing data; and a unit for storing encrypted first authentication data. Means for decrypting the encrypted first authentication data using the supplied delivery key, and means for converting the first authentication data so that the reverse conversion cannot be performed substantially. A first digest creating means for creating a first digest, a means for creating second authentication data based on a password supplied by an operation of an operator, comprising: Means for creating a delivery key and supplying it to the storage means, and creating a second digest representing the second authentication data converted so that the reverse conversion cannot be performed substantially. And the second of the digest creating means that,
Acquiring the first digest from the storage means,
Determining whether or not the first and second digests indicate substantially the same authentication data, and when determining that the authentication data indicates the authentication data, instructing the storage unit to acquire the data from the storage area And a program for functioning as an instruction for requesting storage of the data in the storage area and a means for supplying the data to the storage means.

The computer that executes the program recorded on such a recording medium and the storage means are each configured such that the authentication data stored in the storage means and the authentication data generated from the password supplied to the access means are substantially stored. After confirming that they are the same, the user or the like is permitted to access the storage area of the data storage means. Therefore, if the password is not disclosed to anyone other than the user, the person who accesses the data is authenticated.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a mutual authentication system and a mutual authentication method according to an embodiment of the present invention will be described with reference to the drawings, taking a data recording system including a flash memory as an example.

FIG. 1 shows a physical configuration of the data recording system. As shown, the data recording system includes a memory card 1 and an access device 2.

The memory card 1 includes a control unit 11, a flash memory 12, and a protection ROM (Read Only Memory).
ry) 13 and protected RAM (Random Access Memor)
y) 14 and a general work RAM 15.

The control unit 11 has a CPU (Central Process
ng Unit), and stores program data representing initialization and mutual authentication processing to be described later in the protection ROM 13.
And executes a process represented by the read program data.

The processing represented by the program data includes a mutual authentication processing described later. When the memory card 1 and the access device 2 are mutually accessible as a result of the mutual authentication process, the control unit 11 uniquely assigns the write target data transmitted from the access device 2 to the memory card 1. The data is encrypted by using the obtained card key KKc and then written to the flash memory 12. When data is read from the flash memory 12 in a state where the memory card 1 and the access device 2 can access each other, after reading the data, the data is decrypted using the card key KKc, and then the access is performed. It is supplied to the device 2.

The flash memory 12 is an EEPROM
(Electrically Erasable / Programmable ROM) and the like, in response to an instruction from the control unit 11 and the access device 2,
The stored data is supplied to the control unit 11 and the access device 2, and the data is stored. Flash memory 1
2 is stored in the control unit 11 as described above.
Is stored in an encrypted state using the card key KKc.

Further, the flash memory 12 includes the control unit 1
1 and the access device 2 to collectively erase stored data for each storage area belonging to a predetermined block.

The protection ROM 13 is a PROM (Prog
ramable ROM) and the like, and an initial setting key KK described later.
i, a system key KKs, data eKKc (PWr) and data eKKu (eKKs (KKc)), and program data representing initialization and mutual authentication processing to be described later.

The data eKKu (eKKs (KK
c)) represents data eKKs (KKc) obtained by encrypting a card key KKc using a system key KKs and further encrypting the data eKKs (KKc) using a user key KKu described later.

Further, the data eKKc (PWr) is obtained by replacing the authentication password PWr generated by substantially the same processing as the processing of step S203 described later with the card key K based on the password assigned to the specific user.
It represents the one encrypted using Kc.

Protect RAM 14 and RA for general work
M15 is formed of an SRAM (Static RAM) or the like, and is used as a work area of the control unit 11. Of these, the protection RAM 14 is prohibited from being accessed from the outside by the control unit 11, and when the control unit 11 performs a specific process that needs to prevent the calculation process from leaking to the outside (for example, a step described later). It is used as a work area in the processing of S306 and S308).

The access device 2 includes a control unit 21, an input unit 22, and a storage unit 23. The control unit 21 includes a CPU or the like, reads program data representing initial setting and mutual authentication processing described later from the storage unit 23, and executes a process represented by the read program data.

The input unit 22 includes a keyboard or the like, and supplies information according to a user operation to the control unit 21.

The storage unit 23 is composed of a RAM, a hard disk device and the like, and stores a constant Pkku to be described later and program data representing initial setting and mutual authentication processing. Then, in response to an instruction from the control unit 21, the stored data is supplied to the control unit 21, and the data supplied from the control unit 21 is stored. In addition, the storage unit 23
It is also used as a work area of the control unit 21.

(Operation) Next, the operation of the data recording system will be described with reference to FIGS. (Initial Setting) In this data recording system, for example, when the memory card 1 is inserted into the access device 2 and the user instructs to initialize the memory card 1 using the input unit 22, the processing of the initial setting shown in FIG. I do.

When the initialization process is started, the control unit 21 of the access device 2 waits for the user to input an identification code for identifying the user using the input unit 22.
When the identification code is input (step S10)
1), the control unit 21 transmits the value ID of the identification code to the control unit 11 of the memory card 1 (Step S102).

When the control unit 11 of the memory card 1 receives the value ID of the identification code, the control unit 11 reads the initialization key KKi recorded in advance in the protect ROM 13, and stores the received value ID of the identification code and the read initial value. Setting key KKi
Then, the value of the signature S represented by the right side of Expression 1 is obtained (step S103).

S = dg (ID, KKi)

However, when α and β are arbitrary numbers, d
g (α, β) represents the value of a function (eg, a one-way hash function) that makes it substantially impossible to reverse the values of α and β from the value of dg (α, β) . In the following, dg (α, β) is referred to as “digest” of α using β as a key.

Note that the function used as the digest of α with β as the key is, for example, even if it is logically possible to inversely calculate the values of α and β from the values of the function, the inverse calculation is performed by those who attempt the inverse calculation. Anything can be used as long as it can give a de facto influence such as giving up (for example, having a property that a great deal of time and economic load is required for back calculation).

When the value of the signature S is calculated, the control unit 11
Searches the storage area of the flash memory 12 to determine whether or not there is a signature that has already been written (step S104).

When it is determined that the signature has not been written, the control unit 11 writes the signature S obtained in step S103 into the flash memory 12 (step S103).
105), perform other processing (for example, processing such as formatting of the storage area of the flash memory 12) (step S106), and end the processing.

On the other hand, if it is determined that the signature has already been written, the control unit 11 reads the signature and determines whether the value of the read signature is equal to the value of the signature S obtained in step S103. It is determined (step S107). If it is determined that they are equal, the control unit 11 proceeds to another process (step S106). If it is determined that they are different, the initial setting is interrupted (step S108), and the process ends.

(Mutual Authentication) The memory card 1 and the access device 2 communicate with the access device 2 in accordance with a user's instruction.
Before the device accesses the storage area of the flash memory 12, the mutual authentication process shown in FIG. 3 is performed.

When the mutual authentication process is started, the control unit 21 of the access device 2 first generates two random numbers Ru and Rud and stores them in the storage unit 23 (step S201).
On the other hand, the control unit 11 of the memory card 1 also generates two random numbers Rc and Rcd and stores them in the general work RAM 15 (step S301).

Next, the control unit 21 of the access device 2 waits for the user to input a password PW using the input unit 22. When the password PW is input (step S202), the password is changed to It is divided into a decryption password PWd and an authentication password PWr by a predetermined method (step S203).

Next, the control unit 21 calculates the digest value of the decryption password PWd using the constant Pkku stored in the storage unit 23 as a key, and sets the obtained value as the user key KKu (step S204).

On the other hand, the control unit 11 of the memory card 1 calculates the delivery key information Klc represented by the right side of Expression 2 (step S302), and the control unit 21 of the access device 2
To send the random number Rcd and the delivery key information Klc.

## EQU2 ## Klc = f (Rc, Rcd)

However, when γ and δ are arbitrary numbers, f
(Γ, δ) is substantially impossible to inversely calculate the values of γ and δ from the value of f (γ, δ), and ε, ζ, η
Is an arbitrary number, and represents a value of a function that satisfies the relationship shown in Expression 3. In the following, f (γ, δ)
Is referred to as a “one-way function” of γ and δ.

F (ε, f (ζ, η)) = f (ζ, f (ε,
η))

The value of f (γ, δ) is, for example,
What is necessary is just what is represented by the right side of.

F (γ, δ) = (δγ mod p) (where p is a constant that is a prime number. For any two numbers A and B, (Amod B) is obtained by dividing A by B Represents the remainder of the case)

Also, the function used as the one-way function of γ and δ is logically possible to back-calculate the values of γ and δ from the values of the functions, but the back-calculation is performed by those who attempt the back-calculation. Anything that can give a de facto influence that gives up is acceptable.

When receiving the random number Rcd and the distribution key information Klc from the memory card 1, the control unit 21 of the access device 2 calculates the random number Ru and the distribution key information Klu which is a one-way function of the random number Rcd (step S205).

Next, the controller 21 calculates a random number Ru and a delivery key KKd which is a one-way function of the delivery key information Klc (step S206). Then, the control unit 21 encrypts the user key KKu calculated in step S204 using the delivery key KKd, and encrypts the encrypted user key e.
KKd (KKu) is created (step S207).

Next, the control unit 21 transmits the encrypted user key eKKd (KKu), the delivery key information Klu, and the random number Rud to the control unit 11 of the memory card 1,
The delivery key KKd remaining in the storage unit 23 is deleted (step S208).

The control unit 11 of the memory card 1 stores the encrypted user key eKKd (KKu), the delivery key information Kl
When u and the random number Rud are received, the values of the random number Rc and the one-way function f (Rc, Klu) of the distribution key information Klu are calculated and stored in the general work RAM 15 (step S30).
3).

F (Rc, calculated in step S303)
Klu) and the value of the delivery key KKd calculated by the control unit 21 of the access device 2 in step S206.
There is a relationship represented by Equation 5. That is, the value of f (Rc, Klu) calculated in step S303 becomes equal to the value of the delivery key KKd if the calculation is performed using the correct values of Rc and Klu.

[0055]

F (Rc, Klu) = f (Rc, f (Ru, Rcd)) = f (Ru, f (Rc, Rcd)) = KKd

Next, the control unit 11 transmits the encrypted user key eKKd received from the control unit 21 of the access device 2.
(KKu) with the delivery key K calculated in step S303.
Decryption is performed using Kd to obtain a user key KKu, which is stored in the general work RAM 15 (step S304). Then, the control unit 11 deletes the delivery key KKd remaining in the general work RAM 15 (step S305).

Next, the control unit 11 transmits the data eKKu (e
KKs (KKc)) is read from the protection ROM 13 and stored in the protection RAM 14. Then, the control unit 11 first sets the data eKKu (eKKs (KKc))
Is decrypted using the user key KKu, and the data eKKs
(KKc). Further, the system key KKs is read from the protection ROM 13 and data eKKs (KK
c) is decrypted using the system key KKs to obtain a card key KKc (step S306).

When performing the process of step S306, the control unit 11 sets the protection RAM 14 as a work area.
Is used. Further, when data generated during the processing, for example, data eKKs (KKc) is temporarily stored,
The data is stored in the protection RAM 14.

When the card key KKc is obtained, the control unit 1
1 stores the card key KKc in the protect RAM 14 and stores the user key K in the general work RAM 15.
Ku is erased (step S307).

Next, the control unit 11 sets the decryption password P
Data eKKc obtained by encrypting Wr with a card key KKc
(PWr) is read from the protect ROM 13. Then, the data eKKc (PWr) is decrypted using the card key KKc, a decryption password PWr is obtained, and stored in the protection RAM 14 (step S308). Note that the control unit 11 also uses the protect RAM 14 as a work area when performing the processing in step S308.

Next, the control unit 11 uses the random number Rud as a key to decode the decrypted password P obtained in step S308.
A value of the digest dg (PWr, Rud) of Wr (hereinafter referred to as Dcu) is calculated (step S309), and the obtained digest value Dcu is transmitted to the control unit 21 of the access device 2.

The control unit 21 of the access device 2 that has received the digest value Dcu uses the random number Rud as a key and creates the decryption password PW created by itself in step S203.
r, the digest dg (PWr, Rud) value (hereinafter D
uu) (step S209).

Next, the control unit 21 determines whether or not the digest Duu calculated by itself is substantially equal to the digest Dcu received from the control unit 11 of the memory card 1 (step S210).

When it is determined that the digests Duu and Dcu are substantially equal, the control unit 21 uses the input unit 22 to input the password PWr using the user indicated by the authentication password PWr stored in the memory card 1. It is determined that the input user is the same person, and the memory card 1 is authenticated as a valid memory card. And a random number Rc
d, and the digest dg (PWr, R) of the decryption password PWr created by itself in step S203.
cd) (hereinafter referred to as Duc) (Step S)
211), and transmits the obtained digest value Duc and information indicating the authentication result to the control unit 11 of the memory card 1.

If it is determined in step S210 that the digests Duu and Dcu are different from each other, the control unit 21 determines that the memory card 1 is invalid or that the user has input an invalid password PW. ,
The process returns to step S201.

The control unit 11 of the memory card 1 having received the digest value Duc and the authentication result uses the random number Rcd as a key, and the digest dg (PWr, Rc) of the decrypted password PWr decrypted in step S308 by itself.
d) (hereinafter referred to as Dcc) is calculated (step S).
310).

Next, the control unit 11 determines whether or not the digest Dcc calculated by itself is substantially equal to the digest Duc received from the control unit 21 of the access device 2 (step S311). Digest Dcc and D
uc is determined to be substantially equal, the control unit 1
1 is the data eK stored in the protection ROM 13
It is determined that the user indicated by Kc (PWr) and the user who has input the password PW using the input unit 22 are the same person, and the user who has input the password PW is authenticated. Then, the information indicating the authentication result is stored in the control unit 21 of the access device 2.
To delete the decryption password PWr remaining in the protection RAM 14 (step S312), and ends the processing.

If it is determined in step S311, that the digests Dcc and Duc are different from each other, the control unit 11 determines that the access device 2 is invalid or that the user has input an invalid password PW. ,
The process returns to step S301.

On the other hand, the control unit 21 of the access device 2 that has received the authentication result from the control unit 11 of the memory card 1 transmits the decrypted password PW remaining in the storage area of the storage unit 23.
r is deleted (step S212), and the process ends.

Steps S201 to S212 explained above
When the processing of S301 to S312 is completed, the memory card 1 and the access device 2 permit access to each other thereafter. As a result, the access device 2 accesses the storage area of the flash memory 12 in accordance with the user's instruction, and enters a state where the memory card 1 can be used.

When the access device 2 transmits data to be written to the flash memory 12 after the memory card 1 and the access device 2 permit access to each other, the control unit 11 of the memory card 1 protects the data. The data is encrypted using the card key KKc stored in the RAM 14 and then written to the flash memory 12. When the access device 2 requests reading of data stored in the flash memory 12, the control unit 11
After reading the requested data, the data is decrypted using the card key KKc stored in the protect RAM 14 and then supplied to the access device 2.

The configuration of this data recording system is as follows.
It is not limited to the above. For example, the memory card 1
The flash memory 12 does not need to be provided. For example, instead of the flash memory 12, an SRAM or a silicon disk capable of backing up stored contents may be used, or any other recording medium may be used. Further, the memory card 1 and the access device 2 do not need to be detachably connected to each other, but may be fixedly connected.

The memory card 1 and the access device 2
May store the same delivery key KKd in advance. The delivery key KKd may be delivered using a pair of a public key and a secret key. In this case, for example, the control unit 11 of the memory card 1 creates a pair of a public key and a secret key, and supplies the public key to the access device 2. The control unit 21 of the access device 2 encrypts the delivery key KKd using the supplied public key, and sends the encrypted delivery key K
Kd is sent to the memory card 1. The control unit 11 of the memory card 1 decrypts the encrypted delivery key KKd using the secret key, and obtains the delivery key KKd. Also, the authentication password PWr may be delivered using a pair of a public key and a secret key in the same manner as the delivery key KKd.

Although the embodiments of the present invention have been described above, the mutual authentication system of the present invention can be realized by using a normal computer system without using a dedicated system. For example, by installing the program from a medium (a floppy disk, a CD-ROM, or the like) storing a program for executing the above-described operation into a computer having an arbitrary interface for connecting a memory card, A mutual authentication system that performs the processing can be configured.

The medium for supplying the program to the computer may be a communication medium (medium for temporarily and fluidly holding the program, such as a communication line, a communication network, or a communication system). For example, the program may be posted on a bulletin board (BBS) of a communication network and distributed via the network. And start this program, under the control of the window system,
The above-described processing can be executed by executing the application in the same manner as other applications.

When the OS shares part of the processing,
Alternatively, when the OS constitutes a part of one component of the present invention, a program excluding the part may be stored in the recording medium. Also in this case, in the present invention, it is assumed that the recording medium stores a program for executing each function or step executed by the computer.

[0077]

As described above, according to the present invention,
A mutual authentication system and a mutual authentication method capable of authenticating a person who accesses data stored in a removable storage device are realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a physical configuration of a data storage system according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an initialization process.

FIG. 3 is a flowchart illustrating a process of mutual authentication.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Memory card 11 Control part 12 Flash memory 13 Protect ROM 14 Protect RAM 15 General work RAM 2 Access device 21 Control part 22 Input part 23 Storage part

Claims (12)

[Claims] An access unit configured to create first authentication data based on a password supplied by an operation of an operator; and a delivery key. Means for supplying to the storage means; first digest creation means for creating a first digest representing a result of converting the first authentication data so that the first authentication data cannot be substantially reverse-converted; A second digest creating unit that creates a second digest representing the authentication data converted so that the reverse conversion cannot be performed substantially, and supplies the second digest to the storage unit;
A data storage unit having a storage area for storing data, a unit for storing encrypted second authentication data, and a delivery key supplied from the access unit. Means for decrypting the encrypted second authentication data; and creating a third digest representing a result of the second authentication data being converted so as not to be able to be substantially inversely converted; A third digest creating means for supplying to the means, a fourth digest creating means for creating a fourth digest representing the second authentication data converted so that the reverse conversion cannot be performed substantially, The second digest is obtained from the access means, and it is determined whether or not the second and fourth digests indicate substantially the same authentication data. Storing the data supplied from the access unit in the storage area, acquiring the data from the storage area, and transmitting the data acquired from the storage area to the access unit in accordance with an instruction of the access unit. The access unit acquires the third digest from the storage unit and determines whether the first and third digests indicate the substantially same authentication data. And when it is determined to indicate, to the instruction to request the storage means to acquire the data from the storage area, to the instruction to request storage of the data in the storage area, and to the storage means Means for supplying the data of
A mutual authentication system characterized by the following. 2. The access means creates a user key based on the password, encrypts the user key using the delivery key to create an encrypted user key, and stores the encrypted user key in the Means for supplying to the storage means, the storage means having a storage area substantially inaccessible from the access means, and in the storage area, a system key and the encrypted second Means for storing authentication data and an encrypted unique key; means for decrypting the encrypted user key supplied from the access means using the delivery key; and A unique key decryption means for decrypting using the system key and the decrypted user key; and decrypting the encrypted first authentication data using the decrypted unique key. However, the mutual authentication system of claim 1, and an authentication data decryption means for producing the second authentication data, it is characterized. 3. The storage unit, wherein the access unit issues the instruction requesting storage of the data in the storage area, and supplies the data to be stored in the storage area. Means for encrypting the supplied data using the decrypted unique key and storing the encrypted data in the storage area; and requesting the access means to obtain the data stored in the storage area. Means for obtaining the encrypted data from the storage area, decrypting the data using the decrypted unique key, and supplying the decrypted data to the access means when the instruction is issued. The mutual authentication system according to claim 2, wherein: 4. The method according to claim 1, wherein the unique key decrypting means is configured to supply information generated for decrypting the encrypted unique key and the decrypted unique key to the access means. The mutual authentication system according to claim 2 or 3, further comprising means for preventing the mutual authentication. 5. The authentication data decrypting means according to claim 1, wherein information generated for decrypting said encrypted first authentication data and said second authentication data are supplied to said access means. 5. The mutual authentication system according to claim 2, further comprising means for substantially blocking. 6. An access means, comprising: means for generating a first random number; acquiring first delivery key information from the storage means;
Means for creating the first delivery key based on the delivery key information and the first random number, and obtaining a second random number from the storage means, and based on the second random number and the first random number Means for generating second delivery key information by means of the second delivery key information, and supplying the second delivery key information to the storage means, wherein the storage means generates the second random number and the third random number. Means for creating the first delivery key information based on the second and third random numbers, and supplying the first delivery key information and the second random number to the access means; Means for generating the second delivery key substantially identical to the first delivery key based on the random number of the second delivery key information and the second delivery key information supplied from the access means. Mutual recognition according to any one of claims 1 to 5, characterized in that: System. 7. The access means includes means for generating a fourth random number and supplying the generated fourth random number to the storage means, wherein the first digest creation means includes the first authentication data and the fourth random number. And a means for creating the first digest by determining the value of a one-way function with variables as the variables, wherein the second digest creating means comprises: the first authentication data; the third random number; Means for generating the second digest by obtaining a value of a one-way function having as a variable, the third digest generating means converts the second authentication data and the fourth random number Means for generating the third digest by obtaining a value of a one-way function as a variable, wherein the fourth digest generating means converts the second authentication data and the third random number into variables To be The mutual authentication system according to claim 6, further comprising: means for generating the fourth digest by determining a value of a one-way function. 8. The access means includes: identification information for identifying the operator, supplied in accordance with an operation of the operator;
Means for generating signature information for identifying the operator by performing conversion so that inverse conversion cannot be performed substantially, and for supplying the signature information to the storage means, wherein the storage means is supplied from the access means. Means for acquiring the signature information, and determining whether or not the signature information is stored in the storage area, and when it is determined that the signature information is not stored, the signature information supplied from the access means is When it is stored in the storage area and determined to be stored, whether the stored signature information and the signature information supplied from the access unit indicate substantially the same operator or not. Means for rejecting following the instruction given by the access means when it is determined that the instruction is not shown, the mutual access means according to any one of claims 1 to 7 being provided. Recognition Proof system. 9. A storage device comprising a storage area for storing data, and an access means comprising means for accessing the storage area, wherein the access means is supplied in accordance with an operation of an operator. Means for converting the identification information for identifying the operator so that the inverse conversion cannot be substantially performed, creating signature information for identifying the operator, and supplying the signature information to the storage means; Means for obtaining the signature information supplied from the access means; determining whether the signature information is stored in the storage area; determining that the signature information is not stored; The signature information supplied from the storage unit is stored in the storage area, and when it is determined that the signature information is stored, the stored signature information and the signature information supplied from the access unit are stored. Means for determining whether or not the signature information indicates substantially the same operator, and rejecting to follow the instruction performed by the access means when it is determined that the information does not indicate the same operator. A mutual authentication system characterized by the following. 10. The mutual authentication system according to claim 1, wherein said storage means is detachably connected to said access means. 11. A storage step and an access step, wherein the access step is a step of creating first authentication data based on a password supplied by an operation of an operator, and creating a delivery key. A step of supplying the first authentication data to the storage step; a first digest creation step of creating a first digest representing a result obtained by converting the first authentication data so that the reverse conversion cannot be performed substantially; A second digest creating step of creating a second digest representing the authentication data converted so that the reverse conversion cannot be performed substantially, and supplying the digest to the storing step, wherein the storing step includes: A data storage step including a storage area for storing; a step of storing encrypted second authentication data; Using the delivery key supplied from the access step to decrypt the encrypted second authentication data, and converting the second authentication data so that the reverse conversion cannot be performed substantially. A third digest creating step of creating a third digest representing the second authentication data and supplying the third digest to the access step; and a fourth digest representing a result obtained by converting the second authentication data so that the reverse conversion cannot be performed substantially. A fourth digest creating step of creating, and obtaining the second digest from the access step, determining whether the second and fourth digests show substantially the same authentication data, When determined to indicate, according to the instruction of the access step, storage of the data supplied from the access step in the storage area, Performing the acquisition of the data from the storage area and the supply of the data acquired from the storage area to the access step, wherein the access step acquires the third digest from the storage step Then, it is determined whether or not the first and third digests indicate substantially the same authentication data. When it is determined that the authentication data indicates the authentication data, the storage step includes obtaining the data from the storage area. A mutual authentication method, comprising: the instruction to request, the instruction to request storage of the data in the storage area, and a step of supplying the data to the storage step. 12. A data storage means having a storage area for storing data, means for storing encrypted first authentication data, and said encrypted second authentication data using a supplied delivery key. Means for decrypting the first authentication data, and first digest creation means for creating a first digest representing a result of the first authentication data converted so that the reverse conversion cannot be performed substantially. Means for creating a second authentication data based on a password supplied by an operation of an operator, a means for creating the delivery key and supplying the computer with the computer connected to the storage means, Second digest creating means for creating a second digest representing a result of converting the authentication data of the second authentication data so that the reverse conversion cannot be substantially performed; and storing the first digest in the storage means. Get the strike,
Determining whether or not the first and second digests indicate substantially the same authentication data, and when determining that the authentication data indicates the authentication data, instructing the storage unit to acquire the data from the storage area A computer-readable recording medium for recording an instruction for requesting storage of the data in the storage area and supplying the data to the storage unit, and a program for causing the storage unit to function;