METHOD FOR CONDUCTING DATA ENCRYPTION AND DECRYPTION USING SYMMETRIC CRYPTOGRAPHY ALGORITHM AND TABLE LOOK-UP DEVICE

• US 20150172043A1
• Filed: 06/09/2013
• Published: 06/18/2015
• Est. Priority Date: 06/18/2012
• Status: Active Grant

• Current Assignee: China Iwncomm Co., Ltd
• Original Assignee: China Iwncomm Co., Ltd
• Inventors: Cao, Jun, Yan, Xiang, Li, Zhiyong
• Granted Patent: US 9,374,218 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09C 1/00 Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system cryptographic typewriters G09C3/00
• CPC Class Codes: H04L 2209/122 Hardware reduction or efficient architectures
• CPC Class Codes: H04L 9/0631 Substitution permutation network [SPN], i.e. cipher composed of a number of stages or rounds each involving linear and nonlinear transformations, e.g. AES algorithms
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
• CPC Class Codes: H04L 9/16 the keys or algorithms being changed during operation
• CPC Class Codes: H04L 9/3263 involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823

Abstract

Disclosed are a method for conducting data encryption and decryption using a symmetric cryptography algorithm and a table look-up device. The method comprises: when it is determined that it is required to use S-boxes to look up a table in a symmetric cryptography algorithm, determining all types of S-boxes to be used; for each type of S-box, determining the total number N_i of the type of S-box, and when N_i is larger than 1, determining that the type of S-box meets a multiplexing condition; and when data encryption and decryption are conducted using the symmetric cryptography algorithm, multiplexing at least one type of S-box which meets the multiplexing condition. The present application can reduce the occupation by the symmetric cryptography algorithm of hardware resources under the condition of comparative shortage of hardware resources.

Claims

1. A data encryption and decryption method using a symmetric cryptographic algorithm, comprising:

once it is determined that S boxes are needed to be used to perform table lookup in the symmetric cryptographic algorithm, determining types of all S boxes needed to be used;

for each type of S boxes, determining a total number N_i of S boxes of the type, and in a case that N_i is greater than 1, determining that a reusing condition is satisfied for the type of S boxes; and

reusing at least one type of S boxes, for which the reusing condition is satisfied, in the data encryption and decryption using the symmetric cryptographic algorithm.

2. The method according to claim 1, wherein once it is determined to reuse one type of S boxes satisfying the reusing condition, a reusing way in the following is used:

determining algorithm subunits using the type of S boxes;

in a case that there is only one algorithm subunit using the type of S boxes, determining that after reuse, the number of S boxes of this type is u wherein 1≦

u<

N_i; and

using u S boxes of this type as one table lookup unit, wherein the algorithm subunit uses the table lookup unit to perform table lookup.

3. The method according to claim 1, wherein once it is determined to reuse one type of S boxes satisfying the reusing condition, a reusing way in the following is used:

determining algorithm subunits using the type of S boxes;

in a case that there are at least two algorithm subunits using the type of S boxes, for at least two among the algorithm subunits using the type of S boxes, determining that after reuse, the number of S boxes of this type used by the at least two algorithm subunits is u, wherein 1≦

u<

N_max, and N_max represents the maximum number of S boxes of this type used by one of the at least two algorithm subunits which uses most S boxes before reuse; and

using u S boxes of this type as one table lookup unit, and performing table lookup through using the table lookup unit in time sharing mode by the at least two of the algorithm subunits using the type of S boxes.

4. The method according to claim 1, wherein once it is determined to reuse one type of S boxes satisfying the reusing condition, a reusing way in the following is used:

determining algorithm subunits using the type of S boxes;

in a case that there are at least two algorithm subunits using the type of S boxes, for each one of at least one algorithm subunit among the algorithm subunits using the type of S boxes, determining that after reuse, the number of S boxes of this type used by the algorithm subunit is u_i, where 1≦

u<

N_j, and N_i represents the number of S boxes of this type used by the algorithm subunit before reuse;

using u_i S boxes of this type as one table lookup unit, and performing table lookup using the table lookup unit independently by the algorithm subunit.

5. The method according to claim 1, wherein once it is determined to reuse one type of S boxes satisfying the reusing condition, a reusing way in the following is used:

determining algorithm subunits using the type of S boxes;

in a case that there are at least three algorithm subunits using the type of S boxes, for each one of at least one algorithm subunit among the algorithm subunits using the type of S boxes, determining that after reuse, the number of S boxes of this type used by the algorithm subunit is wherein 1≦

u<

N_j, and N_i is the number of S boxes of this type used by the algorithm subunit before reuse;

using u_i S boxes of this type as one table lookup unit, and performing table lookup using the table lookup unit independently by the algorithm subunit; and

for at least two among the at least three algorithm subunits using the type of S boxes, determining that after reuse, the number of S boxes of this type used by the at least two algorithm subunits is u_com, wherein 1≦

u_com≦

N_max, and N_max represents the maximum number of S boxes of this type used by one of the at least two algorithm subunits which uses most S boxes before reuse;

using u_com S boxes of this type as one table lookup unit, and performing table lookup through using the table lookup unit in time sharing mode by the at least two of the algorithm subunits using the type of S boxes.

6. The method according to claim 1, wherein for any algorithm subunit, once it is determined that S boxes used by the algorithm subunit are reused selectively, the table lookup unit corresponding to the algorithm subunit is determined according to reuse situation, and the algorithm subunit uses the corresponding table lookup unit to perform table lookup, comprising:

determining a maximum length h of input data of the table lookup unit according to the number of S boxes for the table lookup unit and a length of input data of each S box;

dividing the input data for table lookup performed by the algorithm subunit through using the table lookup unit into k data segments according to a total length l of the input data, wherein k=┌

l/h┐

, ┌

┐

represents rounding up;

executing table lookup operation for k times in a way of, for each time performing the table lookup operation, dividing an input data segment into data units based on the length of input data of the S box, feeding each data unit into the corresponding S box according to a predetermined correspondence relationship to perform the table lookup, and determining output information of the table lookup operation according to the predetermined relationship; and

cascading the output information from the k executions of the table lookup to acquire a table lookup result.

7. The method according to claim 1, wherein the symmetric cryptographic algorithm is AES algorithm, block cipher SM4 algorithm or ZUC stream cipher algorithm.

8. The method according to claim 2, wherein each table lookup unit corresponds to only one hardware module in hardware implementation.

9. The method according to claim 2, wherein the algorithm subunit is an encryption unit, a decryption unit or a key expansion unit.

12. The method according to claim 2, wherein for any algorithm subunit, once it is determined that S boxes used by the algorithm subunit are reused selectively, the table lookup unit corresponding to the algorithm subunit is determined according to reuse situation, and the algorithm subunit uses the corresponding table lookup unit to perform table lookup, comprising:

determining a maximum length h of input data of the table lookup unit according to the number of S boxes for the table lookup unit and a length of input data of each S box;

dividing the input data for table lookup performed by the algorithm subunit through using the table lookup unit into k data segments according to a total length l of the input data, wherein k=┌

l/h┐

, ┌

┐

represents rounding up;

executing table lookup operation for k times in a way of, for each time performing the table lookup operation, dividing an input data segment into data units based on the length of input data of the S box, feeding each data unit into the corresponding S box according to a predetermined correspondence relationship to perform the table lookup, and determining output information of the table lookup operation according to the predetermined relationship; and

cascading the output information from the k executions of the table lookup to acquire a table lookup result.

13. The method according to claim 3, wherein for any algorithm subunit, once it is determined that S boxes used by the algorithm subunit are reused selectively, the table lookup unit corresponding to the algorithm subunit is determined according to reuse situation, and the algorithm subunit uses the corresponding table lookup unit to perform table lookup, comprising:

determining a maximum length h of input data of the table lookup unit according to the number of S boxes for the table lookup unit and a length of input data of each S box;

dividing the input data for table lookup performed by the algorithm subunit through using the table lookup unit into k data segments according to a total length l of the input data, wherein where k=┌

l/h┐

, ┌

┐

represents rounding up;

executing table lookup operation for k times in a way of, for each time performing the table lookup operation, dividing an input data segment into data units based on the length of input data of the S box, feeding each data unit into the corresponding S box according to a predetermined correspondence relationship to perform the table lookup, and determining output information of the table lookup operation according to the predetermined relationship; and

cascading the output information from the k executions of the table lookup to acquire a table lookup result.

14. The method according to claim 4, wherein for any algorithm subunit, once it is determined that S boxes used by the algorithm subunit are reused selectively, the table lookup unit corresponding to the algorithm subunit is determined according to reuse situation, and the algorithm subunit uses the corresponding table lookup unit to perform table lookup, comprising:

determining a maximum length h of input data of the table lookup unit according to the number of S boxes for the table lookup unit and a length of input data of each S box;

dividing the input data for table lookup performed by the algorithm subunit through using the table lookup unit into k data segments according to a total length l of the input data, wherein k=┌

l/h┐

, ┌

┐

represents rounding up;

executing table lookup operation for k times in a way of, for each time performing the table lookup operation, dividing an input data segment into data units based on the length of input data of the S box, feeding each data unit into the corresponding S box according to a predetermined correspondence relationship to perform the table lookup, and determining output information of the table lookup operation according to the predetermined relationship; and

cascading the output information from the k executions of the table lookup to acquire a table lookup result.

15. The method according to claim 5, wherein for any algorithm subunit, once it is determined that S boxes used by the algorithm subunit are reused selectively, the table lookup unit corresponding to the algorithm subunit is determined according to reuse situation, and the algorithm subunit uses the corresponding table lookup unit to perform table lookup, comprising:

determining a maximum length h of input data of the table lookup unit according to the number of S boxes for the table lookup unit and a length of input data of each S box;

dividing the input data for table lookup performed by the algorithm subunit through using the table lookup unit into k data segments according to a total length l of the input data, wherein k=┌

l/h┐

, ┌

┐

represents rounding up;

executing table lookup operation for k times in a way of, for each time performing the table lookup operation, dividing an input data segment into data units based on the length of input data of the S box, feeding each data unit into the corresponding S box according to a predetermined correspondence relationship to perform the table lookup, and determining output information of the table lookup operation according to the predetermined relationship; and

cascading the output information from the k executions of the table lookup to acquire a table lookup result.

16. The method according to claim 3, wherein each table lookup unit corresponds to only one hardware module in hardware implementation.

17. The method according to claim 4, wherein each table lookup unit corresponds to only one hardware module in hardware implementation.

18. The method according to claim 5, wherein each table lookup unit corresponds to only one hardware module in hardware implementation.

19. The method according to claim 3, wherein the algorithm subunit is an encryption unit, a decryption unit or a key expansion unit.

20. The method according to claim 4, wherein the algorithm subunit is an encryption unit, a decryption unit or a key expansion unit.

10. A table look-up device for data encryption and decryption using a symmetric cryptographic algorithm, comprising:

a processing unit for table lookup input data, configured to, in a case that table lookup is needed in the encryption and decryption using the symmetric cryptographic algorithm, process input data for which the table lookup needs to be performed, for feeding into a S box reusing unit;

the S box reusing unit, configured to reuse types of S boxes, which satisfy a reusing condition and are selected to be reused, perform table lookup with the table lookup input data according to a predetermined correspondence relationship, and for each type of S boxes, in a case that a total number N, of S boxes of this type is greater than 1, determine that the S boxes of this type satisfy the reusing condition; and

a processing unit for table lookup output data, configured to process table lookup output information from the S box reusing unit to acquire a table lookup result.

11. The device according to claim 10, wherein the processing unit for table lookup input data is further configured to divide input data corresponding to a table lookup unit used by an algorithm subunit into k data segments according to a total length l of the input data, feed the k data segments into the S box reusing unit in sequence, wherein k=┌

l/h┐

, ┌

┐

represents rounding up, and h is a maximum length of input data of the table lookup unit, which is determined according to the number of S boxes of the table lookup unit used by the algorithm subunit and a length of input data of each S box;

the S box reusing unit is further configured to execute table lookup for k times via the table lookup unit used by the algorithm subunit in a way of, for each time performing the table lookup, dividing an input data segment into data units based on the length of input data of the S boxes, feeding each data unit into corresponding S boxes according to a predetermined correspondence relationship to perform table lookup and determining output information of this execution of table lookup according to the predetermined relationship; and

to output the output information for each execution of table lookup to the processing unit for table lookup output data;

the table look-up device for data encryption and decryption using the symmetric cryptographic algorithm further comprises;

a table lookup counter configured to at each completion of table lookup with one data segment and determine an end of the table lookup operation when counts to k; and

the processing unit for table lookup output data is further configured to buffer output information for each execution of table lookup, and cascade the output information for respective table lookups at the end of the table lookup operation to acquire a table lookup result.