1. HASH ALGORITHMS - Chapter 12
MD5
SHA
RIPEMD-160
HMAC

2. Elementary Operations
MD5
Message Digest
Compression
Elementary Operations

3. MESSAGE DIGEST GENERATION MD5

4. MD5 COMPRESSION FUNCTION

5. ELEMENTARY MD5 OPERATION

6. KEY ELEMENTS OF MD5 B C D || F G H I
Table 9.1 – truth table
B C D || F G H I || || || || || || || ||

7. SECURE HASH ALGORITHM SHA-1
Message Digest
Compression
Elementary Operations

8. SHA-1 COMPRESSION FUNCTION

9. ELEMENTARY SHA OPERATION

10. TRUTH TABLE for ft – SHA-1
B C D || f f f f60..79 | | | | | | | |

11. CREATION OF 80-WORD I/P

12. Comparison: MD5 vs SHA1
MD5 message digest – 128 bits
SHA-1 message digest – 160 bits
Find two messages with same digest:
MD5 – 264 operations
SHA operations

13. message digest lengths: 256, 384, 512
NEW SHA ALGORITHMS
SHA-256
SHA-384
SHA-512
message digest lengths: 256, 384, 512
to provide compatibility with AES
(see Tables 12.3 and 12.4)

14. Elementary Operations
RIPEMD - 160
Message Digest
Compression
Elementary Operations

15. RIPEMD – 160 COMPRESSION FUNCTION

16. RIPEMD – 160 ELEMENTARY OPERATION

17. RIPEMD – data
Tables 12.5 – 12.9

18. HASH FUNCTIONS - comparisons
Table comparison
Table relative performance

19. HMAC – a MAC from a HASH Why? Hash functions (e.g. MD5, SHA-1)
execute faster than Sym. Key (e.g. DES)
HMAC combines HASH with Secret Key
to make a MAC
HMACK(M) = H[(K+ + opad)||H[K+ + ipad)||M]]
Security(H)  Security(HMAC)

20. HMAC STRUCTURE

21. EFFICIENT IMPLEMENTATION of HMAC