ENDECRYPTOR CAPABLE OF PERFORMING PARALLEL PROCESSING AND ENCRYPTION/DECRYPTION METHOD THEREOF

• US 20110123020A1
• Filed: 09/02/2010
• Published: 05/26/2011
• Est. Priority Date: 11/26/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Jisoo, Lee, Woo-Hyun, Choi, Hong-Mook, Feng, Xingguang
• Granted Patent: US 8,666,064 B2
• Time in Patent Office: Days
• 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 2209/20 Manipulating the length of blocks of bits, e.g. padding or block truncation
• CPC Class Codes: H04L 9/0637 Modes of operation, e.g. cipher block chaining [CBC], electronic codebook [ECB] or Galois/counter mode [GCM]

Abstract

An encryption/decryption method of an endecryptor including a plurality of endecryption units supporting an XES mode with tweak and ciphertext streaming (XTS) includes dividing an input data stream into consecutive data units; inputting the divided data units to the endecryption units, respectively; and simultaneously processing the input data units at the respective endecryption units. According to the encryption/decryption method, parallel processing is performed to encrypt/decrypt data at higher speed.

Claims

1. An encryption/decryption method of an endecryptor, the endecryptor including a plurality of endecryption units supporting an XTS encryption mode, the XTS encryption mode being an XOR-encrypt-XOR (XEX) encryption mode with tweak and ciphertext stealing, the method comprising:

dividing an input data stream into a plurality of consecutive data units;

inputting the divided data units to the endecryption units, respectively; and

simultaneously processing the input data units at the respective endecryption units.

2. The encryption/decryption method as set forth in claim 1, wherein the endecryption units receive data units of a predetermined size.

3. The encryption/decryption method as set forth in claim 2, wherein a last data unit and a data unit preceding the last data unit among the consecutive data units are encrypted/decrypted using ciphertext stealing (CTS) when the data stream cannot be divided evenly by the predetermined size.

4. The encryption/decryption method as set forth in claim 3, wherein when the CTS occurs, the last data unit is input to an encryption unit at which the data unit preceding the last data unit is processed.

5. The encryption/decryption method as set forth in claim 1, wherein the endecryptor inputs the consecutive data units to the endecryption units in a parallel processing mode, respectively.

6. The encryption/decryption method as set forth in claim 1, wherein the endecryptor inputs the consecutive data units to one of the endecryption units in a mode that is not a parallel processing mode.

7. The encryption/decryption method as set forth in claim 1, wherein each of the endecryption units uses a block cipher protocol.

8. The encryption/decryption method as set forth in claim 7, wherein the block cipher protocol is the advanced encryption standard (AES) protocol.

9. The encryption/decryption method as set forth in claim 7, wherein simultaneously processing the input data units at the respective endecryption units comprises:

encrypting a tweak value according to a second input key and the block cipher protocol;

performing modular multiplication of the encrypted tweak value by a primitive value;

performing an exclusive OR (XOR) operation on a result value of the modular multiplication and an input data unit;

processing a result value of the XOR operation according to a first input key and the block cipher protocol; and

performing an XOR operation on the result value of the modular multiplication and the processed result value of the XOR operation.

10. The encryption/decryption method as set forth in claim 9, wherein the tweak value is any bit having the same size as data to be processed at the endecryption units.

11. The encryption/decryption method as set forth in claim 9, wherein the primitive value is determined by an exponent corresponding to the sequential number of the consecutive data units.

12. The encryption/decryption method as set forth in claim 9, wherein the modular multiplication of the primitive value is performed by a shift or XOR operation.

13. An endecryptor comprising:

a plurality of endecryption units supporting an XTS encryption mode, the XTS encryption mode being an XOR-encrypt-XOR (XEX) encryption mode with tweak and ciphertext stealing;

a divider configured to divide a data stream into consecutive data units; and

an allocator configured to allocate the divided data units to the endecryption units, respectively, and to input the allocated data units to the endecryption units,

wherein each of the endecryption units simultaneously processes the input data units.

14. The endecryptor as set forth in claim 13, wherein the allocator simultaneously inputs the allocated data units to the endecryption units during one processing period in a parallel processing mode.

15. The endecryptor as set forth in claim 13, wherein each of the endecryption units performs an endecryption operation according to a block cipher protocol by the unit of 128 bits.

16. The endecryptor as set forth in claim 15, wherein a remainder obtained by dividing bytes of the data stream by 16 is used to determine whether ciphertext stealing (CTS) occurs.

17. The endecryptor as set forth in claim 15, wherein a value obtained by dividing bytes of the data stream by 16 is subjected to a floor operation when ciphertext stealing (CTS) does not occur, and a remainder obtained by dividing a value obtained by subtracting 1 from a value obtained through the floor operation by the number of the endecryption units is used to determine an endecryption unit where the last one of the consecutive data units is to be processed.

18. The endecryptor as set forth in claim 17, wherein when the CTS does not occur, a value obtained by dividing the bytes of the data stream by a value obtained by multiplying the number of the endecryption units by 16 is subjected to a ceiling operation to determine a parallel processing count of the endecryption units.

19. The endecryptor as set forth in claim 15, wherein when the CTS occurs, a value obtained by dividing a value obtained by subtracting 16 from bytes of the data stream by a value obtained by multiplying the number of the endecryption units by 16 is used to determine a parallel processing count of the endecryption units.

20. The endecryptor as set forth in claim 15, wherein the block cipher protocol is the advanced encryption standard (AES) protocol.