ENHANCED CHECKSUM SYSTEM

• US 20130326318A1
• Filed: 05/31/2012
• Published: 12/05/2013
• Est. Priority Date: 05/31/2012
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Haswell, Jonathan M.
• Granted Patent: US 11,132,251 B2
• Time in Patent Office: Days
• US Class Current: 714/807
• CPC Class Codes: G06F 11/1004 to protect a block of data words, e.g. CRC or checksum G06F11/1076 takes precedence; security arrangements for protecting computers or computer systems against unauthorized activity G06F21/00
• CPC Class Codes: H03M 13/096 Checksums
• CPC Class Codes: H04L 2209/34 Encoding or coding, e.g. Huffman coding or error correction
• CPC Class Codes: H04L 9/32 including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials

Abstract

Generating data checksum for a data object including multiple data units comprises, for each data unit, obtaining a corresponding address of the data unit, and rotating the data unit based on said corresponding address of the data unit to generate a rotated data unit. A checksum value for the data object is determined based on said rotated data units.

Claims

1. A method of generating a checksum for a data object including multiple data units, comprising:

for each data unit;

obtaining a corresponding address of the data unit;

rotating the data unit based on said corresponding address of the data unit to generate a rotated data unit; and

generating a checksum value for the data object based on said rotated data units.

2. The method of claim 1, wherein rotating a data unit comprises:

generating a hash value from the corresponding address of the data unit using a hashing function; and

rotating the data unit by the hash value to generate a rotated data unit.

3. The method of claim 2, wherein:

the hashed value output is in a range between 0 and the bit size of said data unit.

4. The method of claim 2, wherein:

generating a checksum value for the data object comprises generating an exclusive OR of the rotated data units.

5. The method of claim 2, wherein:

the address of each data unit comprises relative offset of the data unit within the data object.

6. The method of claim 2, further comprising re-computing a checksum value for the data object when a data segment of the data object is to be modified, said re-computing comprising:

generating a checksum for said data segment to be modified;

effectively subtracting the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum;

generating a checksum for said data segment as modified to generate a second intermediate checksum; and

adding the first and the second intermediate checksums to generate a re-computed checksum value for the data object.

7. The method of claim 6, wherein:

effectively subtracting the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum comprises performing an exclusive OR of the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum; and

adding the first and the second intermediate checksums to generate a re-computed checksum for the data object comprises performing an exclusive OR of the first and the second intermediate checksums to generate a re-computed checksum value for the data object.

8. A system for generating a checksum for a data object including multiple data units, comprising:

a rotation module the rotates a data unit based on a corresponding address of the data unit to generate a rotated data unit; and

a checksum module that generates a checksum value for the data object based on said rotated data units.

9. The system of claim 8, wherein the rotation module rotates the data unit by:

utilizing a hash module to generate a hash value from the corresponding address of the data unit using a hashing function; and

rotating the data unit by the hash value to generate a rotated data unit.

10. The system of claim 9, wherein:

the hashed value output is in a range between 0 and the bit size of said data unit.

11. The system of claim 9, wherein:

The checksum module generates a checksum value for the data object by generating an exclusive OR of the rotated data units.

12. The system of claim 9, wherein:

the address of each data unit comprises relative offset of the data unit within the data object.

13. The system of claim 9, wherein the checksum module re-computes a checksum value for the data object when a data segment of the data object is to be modified, by:

generating a checksum for said data segment to be modified;

effectively subtracting the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum;

generating a checksum for said data segment as modified to generate a second intermediate checksum; and

adding the first and the second intermediate checksums to generate a re-computed checksum value for the data object.

14. The system of claim 13, wherein the checksum module:

effectively subtracts the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum by performing an exclusive OR of the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum; and

adds the first and the second intermediate checksums to generate a re-computed checksum for the data object by performing an exclusive OR of the first and the second intermediate checksums to generate a re-computed checksum value for the data object.

15. A computer program product for generating a checksum for a data object including multiple data units, the computer program product comprising:

a tangible storage medium readable by a computer system and storing instructions for execution by the computer system for performing a method comprising;

for each data unit;

obtaining a corresponding address of the data unit;

rotating the data unit based on said corresponding address of the data unit to generate a rotated data unit; and

generating a checksum value for the data object based on said rotated data units.

16. The computer program product of claim 15, comprising:

generating a hash value from the corresponding address of the data unit using a hashing function; and

rotating the data unit by the hash value to generate a rotated data unit.

17. The computer program product of claim 16, wherein:

the hashed value output is in a range between 0 and the bit size of said data unit.

18. The computer program product of claim 16, wherein:

generating a checksum value for the data object comprises generating an exclusive OR of the rotated data units.

19. The computer program product of claim 16, wherein:

the address of each data unit comprises relative offset of the data unit within the data object.

20. The computer program product of claim 16, further comprising re-computing a checksum value for the data object when a data segment of the data object is to be modified, said re-computing comprising:

generating a checksum for said data segment to be modified;

effectively subtracting the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum;

generating a checksum for said data segment as modified to generate a second intermediate checksum; and

adding the first and the second intermediate checksums to generate a re-computed checksum value for the data object.

21. The computer program product of claim 20, wherein:

effectively subtracting the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum comprises performing an exclusive OR of the checksum of said data segment from the checksum of the data object to generate a first intermediate checksum; and

adding the first and the second intermediate checksums to generate a re-computed checksum for the data object comprises performing an exclusive OR of the first and the second intermediate checksums to generate a re-computed checksum value for the data object.