Encryption output data generation method and system

• US 7,925,886 B2
• Filed: 06/13/2007
• Issued: 04/12/2011
• Est. Priority Date: 06/13/2007
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lott, David Robert
• Primary Examiner(s): Pich; Ponnoreay
• Application Number:
  US11/762,125
• Publication Number:
  US 20080310631A1
• Time in Patent Office: 1,399 Days
• Field of Search: 713/189
• US Class Current: 713/180
• CPC Class Codes: H04L 2209/20 Manipulating the length of blocks of bits, e.g. padding or block truncation
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/0643 Hash functions, e.g. MD5, SHA, HMAC or f9 MAC

Abstract

A hashing method and system. The method comprises receiving by a computing system first source data. A first hash function is applied to first source data. A first hash output is generated by the first hash function as a result of applying the first hash function to first source data. The computing system performs an operation relating the first source data with at least a portion of the first hash output to generate second source data. The first hash function is applied to the second source data. A second hash output is generated as a result of applying the first hash function to the second source data.

Claims

1. A method, comprising:

receiving, by a computing system comprising a computer processor, first source data (S1);

first applying, by said computing system, a first hash function to said first source data (S1);

generating as a result of said first applying, by said first hash function, a first hash output (H1);

performing, by said computing system, an operation relating, said first source data (S1) with at least a portion of said first hash output (H1) to generate second source data (S2);

second applying, by said computing system, said first hash function to said second source data (S2); and

generating as a result of said second applying, by said computer processor executing said first hash function, a second hash output (H2), wherein the second hash output (H2) is used to prevent unauthorized access to one or more computing systems including said computing system.

2. The method of claim 1, further comprising:

determining a numerical value (N1) for a first byte of said first hash output (H1); and

determining a total number (N2) of bytes in said first source data (S1).

3. The method of claim 2, further comprising:

calculating, by said computing system, a remainder (R), wherein said remainder (R)=N1 mod N2.

4. The method of claim 3, further comprising:

combining, by said computing system, said first hash output (H1) with a number (N3) of zeros equivalent to a value of said remainder (R) such that said first hash output (H1) comprises said zeros; and

second comparing said total number (N2) of bytes of said first source data (S1) with a number (N4) of bytes comprised by said first hash output (H1) comprising said zeros to determine if said total number (N2) of bytes is greater than said number (N4) of bytes.

5. The method of claim 4, wherein said second comparing determines that said number (N4) of bytes is greater than said total number (N2) of bytes, and wherein said method further comprises:

removing, by said computing system, at least one byte of said first hash output (H1) such that first hash output (H1) does not comprise said at least one byte of said first hash output (H1).

6. The method of claim 4, wherein said second comparing determines that said number (N4) of bytes is not greater than said total number (N2) of bytes.

7. The method of claim 1, wherein said portion of said first hash output (H1) comprises the entire hash output (H1).

8. The method of claim 1, wherein said performing said operation relating said first source data (S1) with said first hash output (H1) comprises XORing said first source data (S1) and said first hash output (H1) to form S1 XOR H1 as said second source data (S2).

9. The method of claim 1, wherein said performing said operation relating said first source data (S1) with said first hash output (H1) comprises concatenating said first source data (S1) with said first hash output (H1) to form S1H1 as said second source data (S2).

10. The method of claim 1, further comprising:

providing at least one support service for at least one of creating, integrating, hosting, maintaining, and deploying computer-readable code in said computing system, wherein the code in combination with the computing system is capable of performing;

said receiving, said first applying, said generating said first hash output (H1), said performing, said second applying, and said generating said second hash output (H2).

11. A computing system comprising a processor and a computer readable memory unit coupled to the processor, said memory unit containing instructions that when executed by the processor implement a hashing method, said method comprising:

receiving, by a computing system, first source data (S1);

first applying, by said computing system, a first hash function to said first source data (S1);

generating as a result of said first applying, by said first hash function, a first hash output (H1);

performing, by said computing system, an operation relating, said first source data (S1) with at least a portion of said first hash output (H1) to generate second source data (S2);

second applying, by said computing system, said first hash function to said second source data (S2); and

generating as a result of said second applying, by said first hash function, a second hash output (H2).

12. The computing system of claim 11, wherein said method further comprises:

determining a numerical value (N1) for a first byte of said first hash output (H1); and

determining a total number (N2) of bytes in said first source data (S1).

13. The computing system of claim 12, wherein said method further comprises:

calculating, by said computing system, a remainder (R), wherein said remainder (R)=N1 mod N2.

14. The computing system of claim 13, wherein said method further comprises:

combining, by said computing system, said first hash output (H1) with a number (N3) of zeros equivalent to a value of said remainder (R) such that said first hash output (H1) comprises said zeros; and

second comparing said total number (N2) of bytes of said first source data (S1) with a number (N4) of bytes comprised by said first hash output (H1) comprising said zeros to determine if said total number (N2) of bytes is greater than said number (N4) of bytes.

15. The computing system of claim 14, wherein said second comparing determines that said number (N4) of bytes is greater than said total number (N2) of bytes, and wherein said method further comprises:

removing, by said computing system, at least one byte of said first hash output (H1) such that first hash output (H1) does not comprise said at least one byte of said first hash output (H1).

16. The computing system of claim 14, wherein said second comparing determines that said number (N4) of bytes is not greater than said total number (N2) of bytes.

17. The computing system of claim 11, wherein said portion of said first hash output (H1) comprises the entire hash output (H1).

18. The computing system of claim 11, wherein said performing said operation relating said first source data (S1) with said first hash output (H1) comprises XORing said first source data (S1) and said first hash output (H1) to form S1 XOR H1 as said second source data (S2).

19. The computing system of claim 11, wherein said performing said operation relating said first source data (S1) with said first hash output (H1) comprises concatenating said first source data (S1) with said first hash output (H1) to form S1H1 as said second source data (S2).

20. A computer program product, comprising a computer readable memory medium having a computer readable program code embodied therein, said computer readable program code comprising an algorithm adapted to implement a hashing method within a computing system, said method comprising:

receiving, by a computing system, first source data (S1);

first applying, by said computing system, a first hash function to said first source data (S1);

generating as a result of said first applying, by said first hash function, a first hash output (H1);

performing, by said computing system, an operation relating, said first source data (S1) with at least a portion of said first hash output (H1) to generate second source data (S2);

second applying, by said computing system, said first hash function to said second source data (S2); and

generating as a result of said second applying, by said first hash function, a second hash output (H2).

21. The computer program product of claim 20, wherein said method further comprises:

determining a numerical value (N1) for a first byte of said first hash output (H1); and

determining a total number (N2) of bytes in said first source data (S1).

22. The computer program product of claim 21, wherein said method further comprises:

calculating, by said computing system, a remainder (R), wherein said remainder (R)=N1 mod N2.

23. The computer program product of claim 22, wherein said method further comprises:

combining, by said computing system, said first hash output (H1) with a number (N3) of zeros equivalent to a value of said remainder (R), wherein said first hash output (H1) additionally comprises said zeros; and

second comparing said total number (N2) of bytes of said first source data (S1) with a number (N4) of bytes comprised by said first hash output (H1) comprising said zeros to determine if said total number (N2) of bytes is greater than said number (N4) of bytes.

24. The computer program product of claim 23, wherein said second comparing determines that said number (N4) of bytes is greater than said total number (N2) of bytes, and wherein said method further comprises:

removing, by said computing system, at least one byte of said first hash output (H1) such that first hash output (H1) does not comprise said at least one byte of said first hash output (H1).

25. The computer program product of claim 23, wherein said second comparing determines that said number (N4) of bytes is not greater than said total number (N2) of bytes.

26. The computer program product of claim 20, wherein said portion of said first hash output (H1) comprises the entire hash output (H1).

27. The computer program product of claim 20, wherein said performing said operation relating said first source data (S1) with said first hash output (H1) comprises XORing said first source data (S1) and said first hash output (H1) to form S1 XOR H1 as said second source data (S2).

28. The computer program product of claim 20, wherein said performing said operation relating said first source data (S1) with said first hash output (H1) comprises concatenating said first source data (S1) with said first hash output (H1) to form S1H1 as said second source data (S2).