JP2005100378A5

JP2005100378A5 -

Info

Publication number: JP2005100378A5
Application number: JP2004246984A
Authority: JP
Filing date: 2004-08-26
Publication date: 2007-09-13
Anticipated expiration: 2024-08-26

Claims

A program execution device for executing a first secure program executed at a first security level and a second secure program executed at a second security level lower than the first security level,
Processing means for switching between a first mode indicating an operation state at the first security level and a second mode indicating an operation state at the second security level;
An external connection invalidating means for separating the processing means from an external device when executing the first secure program;
A program execution apparatus comprising: protection means for protecting the second secure program .

The first secure program holds secret information used in the second secure program,
The processing means operates according to the first secure program,
Performing mutual authentication with the second secure program, sharing a session key,
Encrypt the secret information using the session key,
Send the encrypted secret information to the second secure program
The program execution device according to claim 1.

The secret information held by the first secure program is:
Key information obtained from a secure area of an external recording medium
The program execution device according to claim 2.

The processing means operates according to the first secure program,
For at least a part of the second program, a hash operation is performed using a secret key to obtain a first tamper detection value,
Comparing the second tampering detection value calculated based on at least a part of the second secure program when the second secure program is generated, and the first tampering detection value;
As a result of the comparison, if they do not match, the operation is terminated, and if they match, the operation is continued.
The program execution device according to claim 2.

The second secure program includes a call instruction for calling the first secure program.
The processing means executes the calling instruction,
The second alteration detection value, the start address of the second program, and the size of the second program are sent to the first secure program.
The program execution device according to claim 4.

The protective means is
Prohibiting the processing means from processing an interrupt before the calling instruction is executed by the processing means;
The processing means includes
Sending the encrypted program key to the first secure program by executing the call instruction included in the second secure program;
When the alteration of the second secure program is not detected by executing the first secure program, the encrypted program key received from the second secure program is included in the first secure program. Decrypting with the master key and sending the decrypted program key to the second secure program;
By executing the second secure program, using the program key acquired from the first secure program, the encrypted part of the second secure program is decrypted, and after the program key is deleted, the processing means Allow interrupt handling
The program execution device according to claim 5, wherein:

The program execution device further includes:
An interrupt detection means for detecting the occurrence of an interrupt is provided,
The protective means is
A storage area for writing data when the processing means is operating according to the second secure program;
When the processing means is operating according to the second secure program, when the interrupt detection means detects an interrupt, the data written in the storage area is encrypted, and when the interrupt processing by the processing means is completed, the processing means Decrypts the encrypted data before returning to the execution of the second secure program
The program execution device according to claim 6.

A certificate authority device that embeds a falsification detection value in a protection target program,
Falsification detection value generation means for encrypting the protection target program, performing a hash operation using a secret key based on at least a part of a processing program including the protection target program, and generating a falsification detection value;
Embedding means for embedding the generated falsification detection value in the processing program;
A certificate authority apparatus comprising:

The embedding means further comprises:
The start address of the protection target program in the program execution device and the size of the protection target program are embedded in the processing program.
The certificate authority apparatus according to claim 8.

The certificate authority device further includes:
A program decryption key used for decrypting an encrypted program obtained by encrypting a part of the protection target program is encrypted based on a master key held by a program execution device permitted to execute the protection target program, A key encryption means for generating
The embedding unit further embeds the encryption key in the processing program.
The certificate authority apparatus according to claim 9.

The first secure program sends execution information, which is information necessary for executing the second secure program, to the second secure program.
The program execution device according to claim 1.

At least a part of the second secure program is encrypted, and the execution information held by the first secure program is a program key used for decrypting an encrypted part of the second secure program;
The processing means includes
Sending the program key to the second secure program by executing the first secure program;
By executing the second secure program, the encrypted part of the second secure program is decrypted and executed using the program key acquired from the first secure program.
The program execution device according to claim 11.

A secure program used in a program execution device,
The secure program includes a first secure program executed at a first security level and a second secure program executed at a second security level lower than the first security level;
The first secure program is:
A tamper detection step of detecting whether the second secure program has been tampered with in response to a call to the second secure program;
An external connection disabling step of disconnecting the processor of the program execution device from the external device;
A key sharing step of sharing a common key by authenticating mutual validity with the second secure program;
An information exchange step for exchanging secret information with the second secure program using the shared key,
The second secure program is
A calling step for calling the first secure program before executing the protection target program included in the second secure program;
A key sharing step of sharing the common key by authenticating the mutual validity with the first secure program;
An information exchange step for exchanging secret information with the first secure program using the common key.
A secure program characterized by this.

The protection target program included in the second secure program is encrypted,
The second secure program further includes:
An interrupt prohibition step that prohibits interrupt processing;
An acquisition step of obtaining a program decryption key used for decryption of the encrypted program to be protected after interrupt processing is prohibited;
A decryption step of decrypting the protection target program using the program decryption key;
The secure program according to claim 13, comprising:

A computer-readable recording medium recording a secure program used in a program execution device,
The secure program includes a first secure program executed at a first security level and a second secure program executed at a second security level lower than the first security level;
The first secure program is:
A tamper detection step of detecting whether the second secure program has been tampered with in response to a call to the second secure program;
An external connection disabling step of disconnecting the processor of the program execution device from the external device;
A key sharing step of sharing a common key by authenticating mutual validity with the second secure program;
An information exchange step for exchanging secret information with the second secure program using the shared key,
The second secure program is
A calling step for calling the first secure program before executing the protection target program included in the second secure program;
A key sharing step of sharing the common key by authenticating the mutual validity with the first secure program;
An information exchange step for exchanging secret information with the first secure program using the common key.
A recording medium characterized by the above.

A program execution method used in a program execution device for executing a first secure program executed at a first security level and a second secure program executed at a second security level lower than the first security level. There,
A processing step of switching between a first mode indicating an operation state at the first security level and a second mode indicating an operation state at the second security level;
An external connection disabling step of disconnecting the processing means from an external device when executing the first secure program;
A protection step for protecting the second secure program;
A program execution method comprising: