JPH02187888A - Certification system - Google Patents

Abstract

PURPOSE:To secure the security between applications by selecting key data based on received designated data and ciphering the received data using the selected key data. CONSTITUTION:A terminal equipment 20 generates random number data by a random number generating part 22 and transmits it by a certification preparation command to an IC card 10. In the card 10, when the certification preparation command is received, random number data are generated by a random number generating part 12 and transmitted to the terminal 20. The terminal 20 searches the key data number of ciphering key data designated form the card 10 out of a key list held by the terminal itself and takes out corresponding key data. Further, the terminal 20 ciphers the random number data from the card 10 by the key data in ciphering part 23 using ciphering algorithm. Thus, the key data for recognizing validity to be used in respective applications can be selectively operated, and the security between the application can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Application Field) The present invention relates to an authentication method for confirming the validity of written data when writing data to a memory section in an IC card, for example. .

(Prior Art) In recent years, so-called IC cards, which have a built-in IC chip that has erasable non-volatile memory and control elements such as a CPU that controls them, have been attracting attention as a new portable data storage medium. .

Conventionally, in an IC card system (for example, a shopping system or a credit system) that uses such an IC card, the process of writing data to the IC card (actually the memory section within the IC card), especially when writing transaction data, The center side could not confirm the validity of the transaction data sent to the center (host computer).

Therefore, when an IC card receives a command to write data from a terminal device, the IC card encrypts the write data using key data and an encryption algorithm, and some of the encrypted data is sent to the terminal. send to the device,
An authentication method is being considered in which the terminal device that receives this sends the encrypted data and the written data to a center, and the center verifies the validity of the written data using these data.

(Problem to be solved by the invention) However, with this type of authentication method, as I'C cards are used for multiple purposes, when used in multiple applications, each It is more effective to have different confirmation key data stored by applications in order to ensure security between applications.

Therefore, even if an IC card is used in multiple applications, the present invention makes it possible to selectively operate key data and encryption algorithms for validity confirmation used in each application, thereby ensuring security between applications. The purpose is to provide an authentication method that makes it possible to ensure the following.

Furthermore, in the authentication method described above, if the written data, key data, and encryption algorithm are the same, the encrypted data output from the IC card will also be the same.
There was a problem in that it was difficult to confirm the validity of the original transaction data.

Therefore, the present invention has developed an authentication method that makes it easy to confirm authenticity because even if the written data, key data, and encryption algorithm are the same, the encrypted data output will be different if the writing time is different. The purpose is to provide.

[Structure of the Invention] (Means for Solving the Problems) The authentication method of the present invention includes a first electronic device and a second electronic device that can communicate with the first electronic device,
means for transmitting first data and designation data specifying key data for encrypting the first data from the second electronic device to the first electronic device; When the first data and specified data are received, one key data is selected based on the received specified data from at least one key data prepared in advance, and this selected key data is used to control the received data. means for encrypting the first data;
The electronic device further includes means for transmitting part of the encrypted data to a second electronic device after receiving all of the first data.

Further, the authentication method of the present invention includes a first electronic device and a second electronic device that can communicate with the first electronic device, and the second electronic device communicates with the first electronic device. means for transmitting first data, key data for encrypting the first data, and specified data specifying an encryption algorithm; When receiving, one key data and one encryption algorithm are selected based on the received specified data from at least one key data and at least one encryption algorithm prepared in advance, and the selected key data and means for encrypting the received first data using an encryption algorithm; and in a first electronic device, after receiving all the first data, encrypting some of the encrypted data; and means for transmitting to a second electronic device.

Furthermore, the authentication method of the present invention includes a first electronic device and a second electronic device that can communicate with the first electronic device, On the other hand, the first
and means for transmitting second data having different contents each time; and a first electronic device, upon receiving the first data and second data, transmitting the second data prepared in advance; means for encrypting the received first data using the key data and encryption algorithm; and means for transmitting part of the data to the second electronic device.

(Operation) The present invention specifies one key data from a terminal device (second electronic device) out of a plurality of key data held inside an IC card (first electronic device), and By encrypting written data using key data, even if an IC card is used in multiple applications, the key data for authenticity confirmation used by each application can be selectively used. It becomes possible to ensure security between applications.

The present invention also provides a method for transmitting one key data and one encryption algorithm among a plurality of key data and a plurality of encryption algorithms held inside an IC card (first electronic device) to a terminal device (second electronic device). By encrypting the written data using the specified key data and encryption algorithm, for example, even if the IC card is used in multiple applications, it can be used in each application. It is possible to selectively use the key data and encryption algorithm for validity confirmation, thereby ensuring security between applications.

Furthermore, the present invention provides an I/O from a terminal device (second electronic device).
By encrypting the write data using different data sent to the C card (second electronic device) as a parameter, the write time is reduced even if the write data, key data, and encryption algorithm are the same. If the data is different, the encrypted data output will be different, making it easier to confirm authenticity.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 8 shows an IC card (first electronic device) according to the present invention.
FIG. 2 is a system configuration diagram of a terminal device (second electronic device) that is a higher-level device, and a center (host computer) that is a higher-level device.

The IC card (first electronic device) 10 includes a memory section 11 for storing various data, a random number generation section 12 for generating random number data, an encryption section 13 for encrypting data, and a terminal device 20 to be described later. Contact section 14 for communication
, and a control element 15 such as a CPU that controls these. Among these, the memory section 11, random number generation section 12, encryption section 13, and control element 15 are configured using, for example, one IC chip (or a plurality of IC chips). IC chip)
It is embedded within the IC card body.

The memory section 11 is composed of a non-volatile memory such as EEFROM, and as shown in FIG.
It is largely divided into an area definition table (area) 16 and a data file (area) 17. The data file 17 includes a plurality of areas 18 .・
It is defined as divided into 18 areas...
.are defined by the area definition information 19 in the area definition table 16.

Here, one piece of area definition information includes, for example, an area number (AID) as identification information that specifies an area, information on the start address in memory to which the area is allocated, size information and attribute information that specify the capacity of the area. This is an associated data string. Note that the attribute information is composed of, for example, 1 byte, and if the MSB is "0", it is an encrypted data writing area, and if it is "IJ", it is an input data writing area.

The terminal device (second electronic device) 20 has a function of handling the IC card 10 and has a memory section 21 that stores various data.
, a random number generation section 22 that generates random number data, an encryption section 23 that encrypts data, a keyboard section 24 that inputs data, a display section 25 that displays data, and a contact section that communicates with the IC card 10. 26, Center (
The communication control section 27 communicates online with a host computer 30 via a communication line 31, and a control section 28 such as a CPU that controls these.

Next, in such a configuration, an authentication method according to the present invention will be explained in detail using FIG. 1. Note that the terminal device 20
It is assumed that the memory unit 21 stores a key data list and a key data number (KID) list as shown in the figure.

The key data list is a list that associates key data numbers with key data, and the KID list is a list of only key data numbers that specify key data. On the other hand, the IC card 10 has its own key data list, which is registered (stored) in the internal memory section 11 when the card is issued.

First, the process of mutual authentication performed between the IC card 10 and the terminal device 20 will be explained using steps 1 to 8. First, in step 1, the terminal device 20 generates random number data R1 by the random number generator 22, and uses the authentication preparation command EXCH to send it to the IC.
Send to card 10. At this time, the terminal device 20
The key data number (KID-M) of the key data used to authenticate the card 10 and the specification data of the encryption algorithm (ALG) supported by the terminal device 2 are also transmitted.

Next, in step 2, when the IC card 10 receives the authentication preparation command EXCH, the random number generation unit 12 generates random number data R2, and sends it to the terminal device 2 as a response EXCH to the authentication preparation command EXCH.
Send to 0. At this time, the IC card 10 finds the key data number (KID-N) of the key data used to authenticate the terminal device 20 from its own key list, and uses the specified encryption algorithm (ALG).
) is supported, and set this to alg
It is transmitted to the terminal device 20 together with the random number data R2.

At this time, if the key data number (KID-M) specified by the terminal device 20 does not exist in the key list, or if the key data number (KID-M) used to authenticate the IC card 10 or the terminal device 20 does not exist in the key list, -N) does not exist in the key list or does not support the specified encryption algorithm, the terminal device 20 is notified of this fact.

Next, in step 3, the terminal device 20 searches the key data number (KID-N) of the encrypted key data specified from the IC card 10 from its own key list, and retrieves the corresponding key data (NNNNN). Take it out. Then, the encryption unit 23 uses the encryption algorithm AL
Encrypt random number data R2 from the IC card 10 with key data (NNNNN) using G (-alg),
As a result, the encrypted data C2 is transferred to the authentication command A.
It is transmitted to the IC card 10 by UTH.

Note that in the figure, E indicates a function box that implements encryption.

Next, in step 4, when the IC card 10 receives the authentication command AUTH, the IC card 10 receives the keypad number (KID-N) of the previously transmitted encrypted key data.
from the key list it owns, and extracts the corresponding key data (NNNNNN). Then, the encryption unit 1
3, the key data (N
NNNN) to encrypt the random number data R2 to obtain encrypted data C2X.

Next, in step 5, the IC card 10 compares the encrypted data C2 in the previously received authentication command AUTH with the encrypted data C2X generated in step 4, and obtains the comparison result Y/N.

Next, in step 6, the IC card 10 retrieves the key data (MMMM) corresponding to the key data number (KID-M) of the encrypted key data specified by the terminal device 20 in the authentication preparation command EXCH. Next, the encryption unit 13 uses the encryption algorithm (A L G) to generate the random number data R1 using the key data (MMMMMM).
is encrypted to obtain encrypted data C1. Then, the comparison result Y/N of this encrypted data C1 and step 5 is
It is sent to the terminal device 20 as a response auth to the authentication command AUTH.

Next, in step 7, when the terminal device 20 receives the response auth, the terminal device 20 receives the key data (M M M M M ).

Then, the encryption unit 23 uses the encryption algorithm (
Random number data R1 from the terminal device 20 is encrypted using the key data (~IMMMM) using ALG) to obtain an encrypted pig CIX.

Next, in step 8, the terminal device 20 compares the encrypted data C1 received by the response au th with the encrypted data CIX generated in step 7, and the terminal device 20 compares this comparison result with the encrypted data CIX received by the response au th.
The subsequent system processing is determined based on the comparison result with the IC card 10.

Next, step 9 to step 23 perform 1. A process of writing data from the terminal device 20 to the IC card 10 and confirming the validity of the writing process will be described.

First, in step 9, the terminal device 20 transmits a request to write data to the IC card 10 using a write command WRITE. At this time, the terminal device 20 determines the area number (AID-A) of the write target area for the memory unit 11 in the IC card 10, the number of bytes of write data (
L-1), and the first divided data (Ml, -1) which is divided into the number of bytes that the IC card 10 can receive as input data from the write data (Ml) are transmitted to the IC card 10.

Next, in step 10, the IC card 10 receives the area number (A
The area assigned ID-A) is found from the area definition table 16 in FIG. If it is not found, write a status indicating that the area number is undefined and write the command WR.
The response to the ITE is sent to the terminal device 20 by writing. If found, it is first checked whether the authentication preparation command EXCH or the encryption preparation command 5RND, which will be described later, has been successfully completed.

As a result of this check, if it has not been completed normally,
Response with execution condition incomplete status
e to the terminal device 20.

If the above check has ended normally, the IC card 10 generates initial data R1' using the random number data R1 notified by the previous authentication preparation command EXCH and the card unique value owned within the IC card 10. .

Next, in step 11, the IC card 10 uses the encryption algorithm (ALG) previously specified by the authentication preparation command EXCH and uses the initial data R1' and the encryption algorithm previously notified by the authentication preparation command EXCH. The write data (Ml-1) is encrypted using the key data (MMMMM) corresponding to the key data number (KID-M), and encrypted data (CI-1) is obtained.

Next, the area number (AID-
By referring to the attribute information of area A), it is determined whether the data to be written to the memory unit 11 is input data (Ml-1) or encrypted data (C1-1), and the write process is performed. .

Then, a response -nb- for requesting the next write data is transmitted to the terminal device 20.

Next, upon receiving the response nb-, the terminal device 20
In step 12, the next write data (Ml-
2) is sent to the IC card 10.

Next, in step 13, the next write data (Ml
-2), the IC card 10 uses the encryption algorithm (ALG) again to extract the final 8-byte data of the previously generated encrypted data (C1-1) and the key data number (KID). -M) corresponding key data (
The write data (Ml-2) is encrypted by MMMMM) to obtain encrypted data (CI-2). Next, similarly to step 11, it is determined whether the data to be written to the memory unit 11 is input data (Ml-2) or encrypted data (C1-2), and selectively write processing to the area is performed. Do this. Then, it transmits a response nb- for requesting the next write data to the terminal device 20.

Thereafter, the same processing operations as steps 12 and 13 are repeated.

Now, in step 14, when the terminal device 20 transmits the final data (Ml-n) of the divided data to the IC card 10, in step 15, the IC card 10 performs a similar write process. Then, the last 8 bytes of the finally generated encrypted data (C1-〇) are converted into confirmation information (
ACI) and transmits it to the terminal device 20 in response to the write command WRITE.

That is, in the above process, in order for the terminal device 20 to authenticate the IC card 10 in advance in a mutual authentication procedure,
Key data (MMMM) specified for the IC card 10
M), an encryption algorithm (ALG) and random number data (R1) are used to obtain confirmation information (ACI) for write data M1.

Next, a process of obtaining confirmation information using key data, an encryption algorithm, and random number data different from those described above will be explained using steps 16 to 20. First, in step 16, the terminal device 20
generates new random number data R3, and transmits it to the IC card 10 by the encryption preparation command S_RND. At this time, the key data number (KIDA) of the key data used by the card 10 to generate confirmation information.
), and the encryption algorithm (ALG").

Next, in step 17, when the IC card 10 receives the encryption preparation command 5RND, it finds the key data number (KID-A) from its own key list and obtains the corresponding key data (AAAA). , response 5rnd is transmitted to the terminal device 20.

Next, in step 18, the terminal device 20 transmits a request to write data to the IC card 10 using a write command WRITE. At this time, the terminal device 20
The area number (AID-B) of the area to be written to the memory section 11 in the card 10, the number of bytes of write data (L-2), and the write data (M2) are transmitted. Note that in this step 18, the number of bytes of the write data (M2) is the number of bytes that the IC card 10 can receive as input data.

Next, in step 1, the IC card 10 finds the area assigned the area number (AID-B) from the area definition table 16 in FIG. 2 in the same manner as in step 10. Then, the IC card 10 first checks whether the encryption preparation command 5RND (or authentication preparation command EXCH) has been normally completed. If the process has been completed normally, the IC card 10 generates initial data R3' from the random number data R3 notified by the encryption preparation command 5RND and the card-specific value owned within the IC card 10.

Next, in step 20, the IC card 10 uses the encryption algorithm (ALG') previously specified by the encryption preparation command 5RND to process the initial data R3'.
Then, the write data (M2) is encrypted using the key data (AAAAA) corresponding to the key data number (KID-A) previously notified by the encryption preparation command 5RND, and encrypted data C2 is obtained. Next, by referring to the attribute information of the area with the area number (AID-B) to be accessed, the data to be written to the memory unit]1 can be changed to input data (M2) or encrypted data (C2). Decide whether to write the data and perform the write process. Then, the last 8 bytes of the encrypted data (C2) are sent as confirmation information (AC2) to the terminal device 20 as a response to the write command WRITE.

Note that the IC card 10 confirms the physical position in the memory section 11 based on the head address information and size information in the area definition table 16 shown in FIG. The start address information is the start address value of the corresponding area, and the size information defines the capacity of the area from the start address value.

In addition, the attribute information consists of 1 hide, and its MSB is "
If it is 0, it is an encrypted data write area, and if it is 1.
If it is, it indicates that it is an input data writing area.

Next, in step 21, when the terminal device 20 finishes writing data to the IC card 10, the terminal device 20 inputs random number pigs (R1, R3) corresponding to the written data (Ml, M2),
Key data number (KID-M.

A data write processing list is created using the KID-A), confirmation information (ACI, AC2), and specified algorithm used (ALG ALG'). Note that at this time, the card unique value is also associated with the list. This created list is then sent to the center 30.

Next, in step 22, upon receiving the list from the terminal device 20, the center 30 extracts the write data (Ml) from the list, and retrieves the corresponding key data number (K
IDI-M), the key data (M M M M M
) from the key list owned by the user, and random number data (R1) and encryption algorithm (ALG) that are associated with the transaction list owned by the user.
Confirmation information (ACIX) is generated.

Then, in step 23, the confirmation information (ACI) associated with the list is compared with the confirmation information (ACI Check the validity of the write process.

For write data (M2) and subsequent steps, step 22.
The validity is confirmed by the same process as in 23.

Next, the operation of the IC card 10 will be explained using FIG. 7. First, the control element 15 is electrically activated by a control signal from the terminal device 20, and then outputs initial response data called answer-to-reset to the terminal device 20 (Sl). Then, the control element 15 turns off the authentication preparation command completion flag and the encryption preparation command completion flag (S2), and shifts to an instruction data waiting state.

In this state, when command data is received (S3), the control element 15 first determines whether this command data is the authentication preparation command EXCH shown in FIG. 3 (S4), and if it is determined not to be so, the next Move on to the flow.

In step S4, if it is determined that the authentication preparation command is EXCH, the control element 15 picks up the contents of the key data number (KID) field in the authentication preparation command and inputs the contents of the key data number (KID) field registered in the memory unit ll. The same key data number is found from (S5).

If the key data number is not found (S6
), the control element 15 outputs a key data specification error status (S7), and returns to the instruction data waiting state. if,
If the key data number is found (S6), the control element 15 saves the corresponding key data in the first key buffer on the internal RAM (S8).

Next, the control element 15 checks whether the encryption algorithm is registered in the memory by referring to the encryption algorithm specification data (ALG) field in the authentication preparation command (S9). ) As a result of this check, if the specified encryption algorithm does not exist (SIO), the control element 15 outputs the specified algorithm error status (S11) and returns to the instruction data waiting state. As a result of the above check, if the specified encryption algorithm exists (S10), the control element 15 saves the number of the encryption algorithm (S12).

Next, the control element 15 saves the random number data (R1) in the authentication preparation command to the first random number buffer on the internal RAM (813), and then selects the key data number of the key data for IC card authentication from the previous key list. (KID') is found (S14).

Then, if the key data number is not found (S1
5) The control element 15 outputs the key data unregistered error status 516) and returns to the command data waiting state.

If the key data number is found (S15), the control element 15 saves the corresponding key data in the second key buffer on the internal RAM (S17).

Next, the control element 15 generates random number data R2 by the random number generator 12, and saves it in the second random number buffer on the internal RAM (318). Then, the control element 15 turns on the authentication preparation command completion flag (S19) and transfers the generated random number data R2 to the previous key data number (KJ
D') and the contents of the encryption algorithm designation data (ALG) field in the authentication $preparation command are output to the terminal device 20 as a response exch to the authentication preparation command EXCH (520), and the process returns to the command data waiting state.

In step S4, if it is determined that it is not the authentication rate OR command EXCH, the control element 15 determines whether it is the authentication command AUTH shown in FIG. 4 (521), and if it is determined that it is not, it moves to the next flow.

In step 21, when determining that the authentication command is AUTH, the control element 15 determines whether the authentication preparation command completion flag is turned on (522), and if it is turned off, outputs an execution condition insufficient error status (823). ), returns to the instruction data waiting state.

In step 22, if the authentication preparation command completion flag is on, the control element 15 causes the encryption unit 13 to
The contents of the second random number buffer are encrypted using the contents of the second key buffer as key data for encryption (S24). At this time, the encryption algorithm that corresponds to the saved encryption algorithm number is used.

Then, the control element 15 compares the result of the encryption with the input data sent in the authentication command AUTH.
), the match flag is turned on or off depending on the comparison result (826-528).

Next, the control element 15 causes the encryption unit 13 to encrypt the contents of the first random number buffer using the contents of the first key buffer as key data for encryption (S29). At this time, the same encryption algorithm as above is used. Then, the control element 15 outputs the result of this encryption together with the contents of the matching flag to the terminal device 20 as a response auth to the authentication command AUTH (530).
Return to command data waiting state.

In step S21, if it is determined that the authentication command is not AUTH, the control element 15 performs the encryption/
Determine whether it is $bi command 5RND or not S 31
) If it is determined that this is not the case, move on to the next flow.

In step 31, when determining that it is the encryption preparation command 5RND, the control element 15 picks up the contents of the key data number (KID) field in the encryption preparation command, and selects the contents registered in the memory section 11. Find the same key data number from the key list (S32
).

And if the key data number is not found (33
3), the control element 15 outputs the key data specification error status 534) and returns to the command data waiting state. If the key data number is found (833), the control element 15 saves the corresponding key data in the first key buffer on the internal RAM (S35).

Next, the control element 15 checks whether the encryption algorithm is registered in the memory by referring to the encryption algorithm specification data (ALG) field in the encryption preparation command ( S36). As a result of this check, if the specified encryption algorithm does not exist (S37), the control element 15 outputs the specified algorithm error status (838) and returns to the command data ambush mode. As a result of the above check, if the specified encryption algorithm exists (S37), the control element 15 saves the number of the encryption algorithm (S39).

Next, the control element 15 saves the random number data (R3) in the encryption preparation command to the first random number buffer on the internal RAM (540), then turns on the encryption preparation command completion flag 541), and The encryption preparation command completion status is output to the terminal device 20 (542), and the process returns to the command data waiting state.

In step S31, the encrypted $bi command 5RND
If not, the control element 15 determines whether or not it is the write command WRITE shown in FIG. 6(a) or (b). It is determined whether the command is a data read command) and the process moves to the corresponding process.

In step S51, if it is determined that the write command is WRITE, the control element 15 determines whether the write command is in the format shown in FIG. 6(a) or in the format shown in FIG. 6(b).
52), if it is the write command in FIG. 6(a), refer to the authentication preparation command completion flag and the encryption preparation command completion flag 553), and if either is off (S 54), the condition is inadequate. Output the status (555) and return to the command data waiting state. If either flag is on (S54), control element 1
5 transfers the contents of the data section in the write command to the internal RA
Save to the second write buffer on M (S56).

In step S52, if the write command is shown in FIG. 6(b), the control element 15 determines whether the write command continuation flag held internally is on (S57
). If it is off, the control element 15 outputs a request error status (558) and returns to the command data waiting state.

If it is on, the control element 15 controls the internal RA
The contents of the data section (input data) in the write-back command are added to the contents of the data save buffer on M, and the contents are saved in the internal RAM.
Save to the second write buffer above (S59).

Then, the control element 15 saves only the contents (input data) of the data portion of the write command in the first write buffer on the internal RAM (S60).

Next, the control element 15 checks whether writing succeeding data exists in the input data sent by the write command of FIG. 6(a) or (b) (561), and if writing succeeding data exists, Turn on the subsequent flag 562
), and if there is no subsequent write data, the subsequent flag is turned off (363).

Next, the control element 15 checks whether the number of bytes of data in the second write buffer on the internal RAM is, for example, a multiple of "8" (564), and if so, proceeds to step S70. If not, the control element 15 refers to the subsequent flag and if it is off (S
65) Pad the data in the second write buffer on the internal RAM (for example, add -20-Hex data to the end) L (S66), generate data for a multiple of "8", and proceed to step S70.

If the subsequent flag is on in step S65, the control element 15 leaves the data for a multiple of "8" and moves the remaining data to the data save buffer on the internal RAM (S67). That is, for example, if 18 bytes of data exist in the second write buffer, only 16 bytes of data are left and the remaining 2 bytes are moved to the data save buffer. At this time, the second
If the write buffer is not empty ('568)
, the process moves to step S70.

In step 368, if the second write buffer on the internal RAM is empty (for example, if there is 7 bytes of data in the second write buffer, the second
(Since all the data in the write buffer is moved to the data save buffer, the second write buffer becomes empty as a result).The control element 15 determines whether the area being accessed this time is an area to be encrypted when writing. (S
69). If not, step S71
If so, the process moves to step S79.

Now, in step S70, the control element 15 causes the encryption unit 13 to encrypt the data in the second write buffer on the internal RAM in, for example, CBC mode. At this time, if the continuation flag is off, the content of the first random number buffer on the internal RAM is written using the exclusive OR of the card-specific value, and if the continuation flag is on, the content of the previous write is used. The last 8 bytes of the encrypted data are used as initial values for the current CBC mode encryption.

Further, the contents of the first key buffer are used as the key data at this time, and the encryption algorithm is selectively used depending on the stored encryption algorithm number. When this process ends, the process moves to step S71.

In step S71, the control element 15 determines whether the continuation flag is on, and if so, determines whether the access target area is an area that requires encryption (S72). If the area does not require encryption, the control element 15 writes the number of bytes L of write data in the write command to the contents of the first write buffer on the internal RAM.
The data is written in the access target area of the memory unit 11 by adding an X (37B). In addition, if the area requires encryption, the control element 15 selects a minimum value LX that is a multiple of "8" that is larger than the number of bytes LX of the write data.
' and writes this with the data in the second write buffer added (S74).

If the continuation flag is turned on in step S71, the control element 15 determines whether the access target area is an area that requires encryption (S75). If the area does not require encryption, the control element 15 uses the internal RA
The contents of the first write buffer on M are added to the previously written data and written (S76). If the area requires encryption, the first control element 15 similarly writes the contents of the second write buffer on the internal RAM (S77).
.

Now, after writing the data, the control element 15 judges whether or not the subsequent flag is turned on (878). If it is turned on, it turns on the continuation flag and responds -nb-
S79) Return to command data waiting state. If the subsequent flag is off, the control element 15
It outputs the last 8 bytes of the contents of the second write buffer on the internal RAM, turns off the continuation flag (580), and returns to the instruction data waiting state.

In this way, one key data and one encryption algorithm from among the plurality of key data and plurality of encryption algorithms held inside the IC card are specified from the terminal device, and the specified key data and encryption By encrypting written data using an algorithm, even if an IC card is used in multiple applications, the key data and encryption algorithm for confirming validity can be selectively used in each application. This makes it possible to maintain security between applications.

Note that the random number data R1 and R3 transmitted from the terminal device 20 to the IC card 10 may have the same content each time, but by making the random number data R1 and R3 different each time, the same write data, Even if the key data and encryption algorithm are different, if the writing time is different, the encrypted data output will be different, making it easy to confirm the authenticity.

In this case, by providing, for example, a clock circuit in the terminal device 20 and generating random number data R1 and R3 using time information generated from this clock circuit, it is possible to easily obtain data with different contents each time. .

[Effects of the Invention] As detailed above, according to the authentication method of the present invention, even if an IC card is used in multiple applications, key data and key data for validation used in each application can be used. Encryption algorithms can be used selectively, making it possible to ensure security between applications.

Furthermore, according to the authentication method of the present invention, even if the written data, key data, and encryption algorithm are the same, if the writing time is different, the output encrypted data will be different, making it easy to confirm the authenticity. becomes.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention, and FIG. 1 is a diagram showing a mutual authentication procedure between an IC card and a terminal device and a data writing procedure from the terminal device to the IC card.
Figure 2 is a diagram showing the configuration of the memory section, Figure 3 is the authentication L$8
FIG. 4 is a diagram showing an example format of a command. FIG. 5 is a diagram showing an example format of an encryption preparation command. FIG. 6 is a diagram showing an example format of a write command. FIG. 7 is a flowchart explaining the operation of the IC card, and FIG. 8 is a system configuration diagram of the IC card, terminal device, and center. 10... IC card (first electronic device), 11...
Memory section, 12... Random number generation section, 13... Encryption section, 14... Contact section, 15... Control element, 20
...Terminal device (second electronic device) 21...Memo'
22... Random number generation section, 23... Encryption section, 2
6... Contact section, 27... Communication control section, 28.
...Control unit, 30...Center (host computer)
. Figure 3 Figure 4 Figure 5

Claims (4)

[Claims] (1) Consisting of a first electronic device and a second electronic device that can communicate with the first electronic device, the second electronic device transmits first data and data to the first electronic device. , means for transmitting specification data specifying key data for encrypting the first data; and when the first electronic device receives the first data and the specification data, at least one means for selecting one key data based on the received specified data from among the two key data and encrypting the received first data using the selected key data; , after receiving all the first data, some of the encrypted data is sent to the second
An authentication method characterized by comprising a means for transmitting data to an electronic device. (2) Consisting of a first electronic device and a second electronic device capable of communicating with the first electronic device, the second electronic device transmits first data and data to the first electronic device. , means for transmitting key data for encrypting the first data and specification data specifying an encryption algorithm; selecting one key data and one encryption algorithm from among the at least one key data and at least one encryption algorithm based on the received specified data;
means for encrypting the received first data using the selected key data and encryption algorithm;
After receiving all of the first data, the first electronic device transfers some of the encrypted data to a second electronic device.
An authentication method characterized by comprising a means for transmitting data to an electronic device. (3) Consisting of a first electronic device and a second electronic device capable of communicating with the first electronic device, the second electronic device transmits first data and data to the first electronic device. , means for transmitting second data having different contents each time; and means for transmitting second data having different contents each time;
means for encrypting the received first data using the received second data, key data prepared in advance, and an encryption algorithm; After receiving all the first data, some of the encrypted data is transferred to the second
An authentication method characterized by comprising a means for transmitting data to an electronic device. (4) The authentication method according to claim 1, wherein the first electronic device further comprises at least one memory section and means for storing the received first data in the memory section.