Encryption Processing Device, Encryption Processing Method, and Programme

1. An encryption processing device comprising: circuitry configured to divide input data into a plurality of lines, and to repeatedly execute data conversion processing applying a round function to each line of input data as a round calculation; and output round keys for each round of the data conversion processing; wherein the circuitry is configured to generate a plurality of round keys by dividing a secret key stored beforehand into a plurality of parts; and wherein the plurality of round keys are output such that a constant sequence is not repeated; and wherein the plurality of round keys are classified into a plurality of sets of round keys and one round key from each set of the plurality of sets of round keys is output for each round of the data conversion processing.

2. The encryption processing device according to claim 1 , wherein the circuitry is configured to change an input sequence of the plurality of round keys at units of a plurality of rounds.

3. The encryption processing device according to claim 1 , wherein the circuitry is further configured to input the input data divided into a plurality of lines, perform non-linear conversion processing and linear conversion processing, and execute calculations applying the round keys against the output of the non-linear conversion processing and linear conversion processing.

4. The encryption processing device according to claim 1 , wherein the circuitry is further configured to divide the secret key stored beforehand into the plurality of parts, and generate the plurality of round keys having the same number of bits as the round key input into the round calculation.

5. The encryption processing device according to claim 1 , wherein the circuitry is further configured to divide the secret key stored beforehand into the plurality of parts, and generate the plurality of round keys having a smaller number of bits as the round key input into the round calculation, and perform a plurality of combinations of the plurality of generated round keys to generate a round key having the same number of bits as the round key input into the round calculation.

6. The encryption processing device according to claim 1 , wherein the circuitry is further configured to output a juxtaposed plurality of round keys that are applied to the round calculation for sequential execution.

7. The encryption processing device according to claim 1 , wherein the circuitry includes at least one selector configured to perform a selection supply processing of keys corresponding to the round calculation.

8. The encryption processing device according to claim 1 , wherein the circuitry includes individual selectors corresponding to each set of the plurality of sets of round keys.

9. The encryption processing device according to claim 1 , wherein the circuitry is configured to execute encryption processing to convert plaintext as the input data into ciphertext, and execute decryption processing to convert ciphertext as the input data into plaintext.

10. The encryption processing device according to claim 1 , wherein the circuitry has a generalized Feistel structure.

11. The encryption processing device according to claim 1 , wherein the circuitry has a generalized Feistel structure with 4 data lines.

12. The encryption processing device according to claim 1 , wherein the circuitry has a Type-2 generalized Feistel structure.

13. An encryption processing method to be executed in an encryption processing device, the encryption processing method comprising: dividing input data into a plurality of lines and repeatedly executing, by the encryption processing device, data conversion processing applying a round function to each line of input data as a round calculation; and outputting round keys for each round of the data conversion processing; wherein the outputting includes generating a plurality of round keys by dividing a secret key stored beforehand into a plurality of parts; and wherein the plurality of round keys are output such that a constant sequence is not repeated; and wherein the plurality of round keys are classified into a plurality of sets of round keys and one round key from each set of the plurality of sets of round keys is output for each round of the data conversion processing.

14. A non-transitory computer readable medium including a computer executable program to execute encryption processing in an encryption processing device, the computer executable program comprising: dividing input data into a plurality of lines and repeatedly executing data conversion processing applying a round function to each line of input data as a round calculation; and outputting round keys for each round of the data conversion processing; wherein the outputting includes generating a plurality of round keys by dividing a secret key stored beforehand into a plurality of parts; and wherein the plurality of round keys are output such that a constant sequence is not repeated; and wherein the plurality of round keys are classified into a plurality of sets of round keys and one round key from each set of the plurality of sets of round keys is output for each round of the data conversion processing.

15. An information processing device comprising: a processor configured to execute a program; memory configured to store the program; circuitry configured to divide input data into a plurality of lines, and to repeatedly execute data conversion processing applying a round function to each line of input data as a round calculation; and output round keys for each round of the data conversion processing; wherein the circuitry is configured to generate a plurality of round keys by dividing a secret key stored beforehand into a plurality of parts; wherein the plurality of round keys are output such that a constant sequence is not repeated; and wherein the plurality of round keys are classified into a plurality of sets of round keys and one round key from each set of the plurality of sets of round keys is output for each round of the data conversion processing.

16. The encryption processing device according to claim 1 , wherein the circuitry is configured to perform an XOR operation on one of the plurality of round keys and an output of the round function applied to each line of the input data.