Data encryption apparatus using odd number of shift-rotations and method

• US 6,304,657 B1
• Filed: 12/29/1999
• Issued: 10/16/2001
• Est. Priority Date: 05/26/1999
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ohmori, Motoji, Yokota, Kaoru, Miyaji, Atsuko
• Primary Examiner(s): Hayes, Gail
• Assistant Examiner(s): Leaning, Jeffrey S.
• Application Number:
  US09/474,531
• Time in Patent Office: 657 Days
• Field of Search: 380/28, 380/259, 380/29
• US Class Current: 380/28
• CPC Class Codes: H04L 2209/125 Parallelization or pipelining, e.g. for accelerating processing of cryptographic operations
• CPC Class Codes: H04L 2209/24 Key scheduling, i.e. generating round keys or sub-keys for block encryption
• CPC Class Codes: H04L 9/0625 with splitting of the data block into left and right halves, e.g. Feistel based algorithms, DES, FEAL, IDEA or KASUMI

Abstract

A data converting unit includes a key adding unit for performing an arithmetic addition modulo 2³² for input data F and subkey data Ki and outputting the outcome as data G, and a data substituting unit for performing an exclusive-OR operation for corresponding bits in data Rot7(G) obtained by shift-rotating the data G by 7 bits toward higher-order bit positions, data Rot1(G) obtained by shift-rotating the data G by 1 bit toward higher-order bit positions, and the data G itself.

Claims

1. A data encryption apparatus provided with a data converting device for converting n-bit input data to n-bit output data, the data converting device comprising:

shift-rotating means for generating k sets of data by shift-rotating the n-bit input data respectively by S1 bits, S2 bits, . . . , and Sk bits, S1, S2, . . . , and Sk being nonnegative integers less than n, and k being an odd number no less than 3; and

data combining means for combining together the k sets of data to generate the n-bit output data.

2. The data encryption apparatus of claim 1,

wherein the shift-rotating unit includes:

m rotating units for shift-rotating the n-bit input data respectively by S1 bits, S2 bits, . . . , and Sm bits, S1, S2, . . . , and Sm being nonnegative integers less than n, and m being an integer no less than 3;

a key data acquiring unit for acquiring key data; and

a selecting unit for selecting k rotating units from the m rotating units based on the acquired key data so that the k sets of data are generated as a result of shift-rotations of the n-bit input data by the selected k rotating units.

3. The data encryption apparatus of claim 1,

wherein the data converting device further comprises key combining means for generating combination data by combining the n-bit input data with key data given beforehand, prior to the shift-rotations by the shift-rotating means, and

wherein the shift-rotating means shift-rotates the combination data generated by the key combining means.

4. The data encryption apparatus of claim 3,

wherein the shift-rotating means includes k rotating units for shift-rotating the combination data respectively by S1 bits, S2 bits, . . . , and Sk bits.

5. The data encryption apparatus of claim 4,

wherein the k rotating units are signal lines that have wiring patterns for shift-rotating the combination data respectively by S1 bits, S2 bits, . . . , and Sk bits.

6. The data encryption apparatus of claim 5,

wherein the key combining means is one of an arithmetic adder and an exclusive-OR gate, and

wherein the data combining means is an exclusive-OR gate.

7. The data encryption apparatus of claim 1,

wherein the data combining means combines key data given beforehand with n-bit data obtained by combining together the k sets of data, to generate the n-bit output data.

8. The data encryption apparatus of claim 1,

wherein the shift-rotating means includes:

k rotating units for shift-rotating the n-bit input data respectively by specified rotation amounts;

a key data acquiring unit for acquiring key data; and

a rotation amount determining unit for determining values of S1, S2, . . . , and Sk based on the acquired key data and specifying, for the k rotating units, S1 bits, S2 bits, . . . , and Sk bits as the respective rotation amounts, and

wherein the k rotating units shift-rotate the n-bit input data respectively by S1 bits, S2 bits, . . . , and Sk bits as specified by the rotation amount determining unit.

9. The data encryption apparatus of claim 1,

wherein the shift-rotating means includes:

m rotating units for shift-rotating the n-bit input data respectively by S1 bits, S2 bits, . . . , and Sm bits, S1, S2, . . . , and Sm being nonnegative integers less than n, and m being an integer no less than 3;

a key data acquiring unit for acquiring key data; and

a selecting unit for selecting k rotating units from the m rotating units based on the acquired key data so that the k sets of data are generated as a result of shift-rotations of the n-bit input data by the selected k rotating units.

10. A data encryption method provided with a data converting step for converting n-bit input data to n-bit output data, the data converting step comprising:

a shift-rotating substep for generating k sets of data by shift-rotating the n-bit input data respectively by S1 bits, S2 bits, . . . , and Sk bits, S1, S2, . . . , and Sk being nonnegative integers less than n, and k being an odd number no less than 3; and

a data combining substep for combining together the k sets of data to generate the n-bit output data.

11. The data encryption method of claim 10,

wherein the data converting step further comprises a key combining substep for generating combination data by combining the n-bit input data with key data given beforehand, prior to the shift-rotations by the shift-rotating substep, and

wherein the shift-rotating substep shift-rotates the combination data generated by the key combining means.

12. The data encryption method of claim 10,

wherein the data combining substep combines key data given beforehand with n-bit data obtained by combining together the k sets of data, to generate the n-bit output data.

13. The data encryption method of claim 10,

wherein the shift-rotating substep includes:

a key data acquiring substep for acquiring key data;

a rotation amount determining substep for determining value s of S1, S2, . . . , and Sk based on the acquired key data; and

a rotating substep for shift-rotating the n-bit input data by S1 bits, S2 bits, . . . , and Sk bits independently.

14. The data encryption method of claim 10,

wherein the shift-rotating substep includes:

a key data acquiring substep for acquiring key data;

a selecting substep for selecting k values of S1, S2, . . . , and Sk from m values of S1, S2, . . . , and Sm which are predetermined based on the acquired key data, S1, S2, . . . , and Sm being nonnegative integers less than n, and m being an integer no less than 3; and

a rotating substep for shift-rotating the n-bit input data by S1 bits, S2 bits, . . . , and Sk bits independently.

15. A computer-readable storage medium storing a data encryption program provided with a data converting step for converting n-bit input data to n-bit output data, the data converting step comprising:

a shift-rotating substep for generating k sets of data by shift-rotating the n-bit input data respectively by S1 bits, S2 bits, . . . , and Sk bits, S1, S2, . . . , and Sk being nonnegative integers less than n, and k being an odd number no less than 3; and

a data combining substep for combining together the k sets of data to generate the n-bit output data.

16. The storage medium of claim 15,

wherein the data converting step further comprises a key combining substep for combining the n-bit input data with key data given beforehand, prior to the shift-rotations by the shift-rotating substep, and

wherein the shift-rotating substep shift-rotates the n-bit input data combined with the key data.

17. The storage medium of claim 15,

wherein the data combining substep combines key data given beforehand with n-bit data obtained by combining together the k sets of data, to generate the n-bit output data.

18. The storage medium of claim 15,

wherein the shift-rotating substep includes:

a key data acquiring substep for acquiring key data;

a rotation amount determining substep for determining values of S1, S2, . . . , and Sk based on the acquired key data; and

a rotating substep for shift-rotating the n-bit input data by S1 bits, S2 bits, . . . , and Sk bits independently.

19. The storage medium of claim 15,

wherein the shift-rotating substep includes:

a key data acquiring substep for acquiring key data;

a selecting substep for selecting k values of S1, S2, . . . , and Sk from m values of S1, S2, . . . , and Sm which are predetermined based on the acquired key data, S1, S2, . . . , and Sm being nonnegative integers less than n, and m being an. integer no less than 3; and

a rotating substep for shift-rotating the n-bit input data by S1 bits, S2 bits, . . . , and Sk bits independently.

20. A data encryption apparatus provided with a data converting device for converting n-bit input data to n-bit output data, the data converting device comprising:

a shift-rotating unit for generating k sets of data by shift-rotating the n-bit input data respectively by S1 bits, S2 bits . . . , and Sk bits, S1, S2, . . . , and Sk being nonnegative integers less than n, and k being an odd number no less than 3; and

a data combining unit for combining together the k sets of data to generate the n-bit output data.

21. The data encryption apparatus of claim 20,

wherein the data converting device further comprises key combining unit for combining the n-bit input data with key data given beforehand to provide combination data, prior to the shift-rotations by the shift-rotating unit, and

wherein the shift-rotating unit shift rotates the combination data.

22. The data encryption apparatus of claim 21,

wherein the shift-rotating unit includes k rotating units for shift-rotating the n-bit input data respectively by S1 bits, 2 bits, . . . , and Sk bits.

23. The data encryption apparatus of claim 22,

wherein the k rotating units are signal lines that have wiring patterns for shift-rotating the n-bit input data respectively by S1 bits, S2 bits, . . . , the Sk bits.

24. The data encryption apparatus of claim 23,

wherein the key combining unit is one of an arithmetic adder and an exclusive-OR gate, and

wherein the data combining unit is an exclusive-OR gate.

25. The data encryption apparatus of claim 20,

wherein the data combining unit combines key data given beforehand with n-bit data obtained by combining together the k sets of data, to generate the combination data.

26. The data encryption apparatus of claim 20,

wherein the shift-rotating unit includes:

k rotating units for shift-rotating the n-bit input data respectively by specified rotation amounts;

a key data acquiring unit for acquiring key data; and

a rotation amount determining unit for determining values of S1, S2, . . . , and Sk based on the acquired key data and specifying, for the k rotating units, S1 bits, S2 bits, . . . , and Sk bits as the respective rotation amounts, and

wherein the k rotating units shift-rotate the n-bit input data respectively by S1 bits, S2 bits, . . . , and Sk bits as specified by the rotation amount determining unit.