Information processing system, information processing method, and information processing program
To provide an architecture information processing system having a small circuit size capable of reducing power consumption and cost, on which system a circuit simultaneously executing encryption processing and message authentication (falsification detection processing) can be mounted. An information processing system includes at least: a parameter storage section that retains an initialization vector used as a starting block of concatenation and an encryption key used for encryption; a one-way hash calculation section that executes a one-way hash calculation as a technique for realizing message authentication and functioning in place of the conventional common key block encryption (DES encryption) operation as an encryption operation section of a block encryption mode use section performing encryption processing and/or decryption processing as a CFB mode and/or an OFB mode; and a key overlay operation section that performs calculation for overlaying an encryption key retained in the parameter storage unit on data input to the encryption operation section.
1. An information processing system that performs authentication using hash calculation, wherein
said system is configured to:
divide a plain text to be encrypted into n (n is a natural number) plain text blocks;
set a first set value, which differs for each plain text, in the plain text to be encrypted;
perform a hash calculation for a first calculation result which is obtained as a result of a first calculation performed for the first set value and an encryption key to output a first hash calculation result;
output a result which is obtained as a result of a second calculation performed for an i-th (i is a natural number satisfying i≦n) hash calculation result and an i-th plain text block as an encrypted i-th cipher text block; and
perform a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th hash calculation result and encryption key to output an (i+1)th hash calculation result.
2. The information processing system according to claim 1 , wherein
said information processing system is further configured to adopt an encrypted cipher text as the plain text to obtain an original plain text as an encryption result.
3. The information processing system according to claim 1 , comprising:
block encryption mode use means for performing a hash calculation for a second calculation result obtained as the first calculation performed for the i-th hash calculation result and encryption key or i-th cipher block and encryption key to output an (i+1)th hash calculation result and selecting/setting an operand to be calculated by the first calculation at the time when the (i+1)th hash calculation result is output;
one-way hash calculation means for performing a hash calculation in the block encryption mode use means; and
parameter storage means for retaining the first set value which differs for each plain text and encryption key used for encryption processing.
4. The information processing system according to claim 1 , wherein
the first set value stored in the parameter storage means includes an initial vector which is managed such that it becomes unique not for each calculation performed by the hash calculation means but for each plain text and an encryption key which is common in a period during which initial vectors do not overlap with each other.
5. The information processing system according to claim 1 , wherein
the first calculation includes a bit concatenation calculation, an exclusive OR calculation, and a calculation that alternately mixes both the bit concatenation calculation and exclusive OR calculation.
6. The information processing system according to claim 1 , wherein
the second calculation is an exclusive OR calculation.
7. An information processing system that performs authentication using hash calculation, wherein
said system is configured to:
divide a plain text to be encrypted into n (n is a natural number) plain text blocks;
set a first set value, which differs for each plain text, in the plain text to be encrypted;
perform a hash calculation for a first calculation result which is obtained as a result of a first calculation performed for the first set value and an encryption key to output a first hash calculation result;
output a result which is obtained as a result of a second calculation performed for an i-th (i is a natural number satisfying i≦n) hash calculation result and an i-th plain text block as an encrypted i-th cipher text block; and
perform a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th cipher text block and encryption key to output an (i+1)th hash calculation result.
8. The information processing system according to claim 7 , wherein
said system is further configured to:
adopt an encrypted cipher text as the plain text; and
perform a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th plain text block and encryption key to output an (i+1)th hash calculation result, in place of performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th cipher text block and encryption key to output an (i+1)th hash calculation result, to obtain an original plain text.
9. An information processing method that performs authentication using hash calculation, comprising:
dividing a plain text to be encrypted into n (n is a natural number) plain text blocks;
setting a first set value, which differs for each plain text, in the plain text to be encrypted;
performing a hash calculation for a first calculation result which is obtained as a result of a first calculation performed for the first set value and an encryption key to output a first hash calculation result;
outputting a result which is obtained as a result of a second calculation performed for an i-th (i is a natural number satisfying i-≦n) hash calculation result and an i-th plain text block as an encrypted i-th cipher text block; and
performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th hash calculation result and encryption key to output an (i+1)th hash calculation result.
10. The information processing method according to claim 9 , further comprising:
adopting an encrypted cipher text as the plain text to obtain an original plain text as an encryption result.
11. The information processing method according to claim 9 , comprising:
a block encryption mode use step of performing a hash calculation for a second calculation result obtained as the first calculation performed for the i-th hash calculation result and encryption key or i-th cipher block and encryption key to output an (i+1)th hash calculation result and selecting/setting an operand to be calculated by the first calculation at the time when the (i+1)th hash calculation result is output;
a one-way hash calculation step of performing a hash calculation in the block encryption mode use step; and
a parameter storage step of retaining the first set value which differs for each plain text and encryption key used for encryption processing.
12. The information processing method according to claim 9 , wherein
the first set value stored in the parameter storage step includes an initial vector which is managed such that it becomes unique not for each calculation performed by the hash calculation means but for each plain text and an encryption key which is common in a period during which initial vectors do not overlap with each other.
13. The information processing method according to claim 9 , wherein
the first calculation includes a bit concatenation calculation, an exclusive OR calculation, and a calculation that alternately mixes both the bit concatenation calculation and exclusive OR calculation.
14. The information processing method according to claim 9 , wherein
the second calculation is an exclusive OR calculation.
15. An information processing method that performs authentication using hash calculation, comprising:
dividing a plain text to be encrypted into n (n is a natural number) plain text blocks;
setting a first set value, which differs for each plain text, in the plain text to be encrypted;
performing a hash calculation for a first calculation result which is obtained as a result of a first calculation performed for the first set value and an encryption key to output a first hash calculation result;
outputting a result which is obtained as a result of a second calculation performed for an i-th (i is a natural number satisfying i≦n) hash calculation result and an i-th plain text block as an encrypted i-th cipher text block; and
performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th cipher text block and encryption key to output an (i+1)th hash calculation result.
16. The information processing method according to claim 15 , further comprising:
adopting an encrypted cipher text as the plain text; and
performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th plain text block and encryption key to output an (i+1)th hash calculation result, in place of performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th cipher text block and encryption key to output an (i+1)th hash calculation result, to obtain an original plain text.
17. An information processing program that performs authentication using hash calculation, allowing a computer to execute processing of:
dividing a plain text to be encrypted into n (n is a natural number) plain text blocks;
setting a first set value, which differs for each plain text, in the plain text to be encrypted;
performing a hash calculation for a first calculation result which is obtained as a result of a first calculation performed for the first set value and an encryption key to output a first hash calculation value;
outputting a result which is obtained as a result of a second calculation performed for an i-th (i is a natural number satisfying i≦n) hash calculation result and an i-th plain text block as an encrypted i-th cipher text block; and
performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th hash calculation result and encryption key to output an (i+1)th hash calculation result.
18. The information processing program according to claim 17 , further allowing a computer to execute processing of adopting an encrypted cipher text as the plain text to obtain an original plain text as an encryption result.
19. The information processing program according to claim 17 , allowing a computer to execute processing of:
a block encryption mode use step of performing a hash calculation for a second calculation result obtained as the first calculation performed for the i-th hash calculation result and encryption key or i-th cipher block and encryption key to output an (i+1)th hash calculation result and selecting/setting an operand to be calculated by the first calculation at the time when the (i+1)th hash calculation result is output;
a one-way hash calculation step of performing a hash calculation in the block encryption mode use step; and
a parameter storage step of retaining the first set value which differs for each plain text and encryption key used for encryption processing.
20. The information processing program according to claim 17 , wherein
the first set value stored in the parameter storage step includes an initial vector which is managed such that it becomes unique not for each calculation performed by the hash calculation means but for each plain text and an encryption key which is common in a period during which initial vectors do not overlap with each other.
21. The information processing program according to claim 17 , wherein
the first calculation includes a bit concatenation calculation, an exclusive OR calculation, and a calculation that alternately mixes both the bit concatenation calculation and exclusive OR calculation.
22. The information processing program according to claim 17 , wherein
the second calculation is an exclusive OR calculation.
23. An information processing program that performs authentication using hash calculation, allowing a computer to execute the processing of:
dividing a plain text to be encrypted into n (n is a natural number) plain text blocks;
setting a first set value, which differs for each plain text, in the plain text to be encrypted;
performing a hash calculation for a first calculation result which is obtained as a result of a first calculation performed for the first set value and an encryption key to output a first hash calculation value;
outputting a result which is obtained as a result of a second calculation performed for an i-th (i is a natural number satisfying i≦n) hash calculation result and an i-th plain text block as an encrypted i-th cipher text block; and
performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th cipher text block and encryption key to output an (i+1)th hash calculation result.
24. The information processing program according to claim 23 , allowing a computer to execute processing of:
adopting an encrypted cipher text as the plain text; and
performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th plain text block and encryption key to output an (i+1)th hash calculation result, in place of performing a hash calculation for a second calculation result which is obtained as a result of the first calculation performed for the i-th cipher text block and encryption key to output an (i+1)th hash calculation result, to obtain an original plain text.