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HASH ALGORITHMS - Chapter 12

MD5 SHA RIPEMD-160 HMAC. HASH ALGORITHMS - Chapter 12. Message Digest Compression Elementary Operations. MD5. MESSAGE DIGEST GENERATION MD5. MD5 COMPRESSION FUNCTION. ELEMENTARY MD5 OPERATION. Table 9.1 – truth table B C D || F G H I

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HASH ALGORITHMS - Chapter 12

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

  2. Message Digest • Compression • Elementary Operations MD5

  3. MESSAGE DIGEST GENERATIONMD5

  4. MD5 COMPRESSION FUNCTION

  5. ELEMENTARY MD5 OPERATION

  6. Table 9.1 – truth table • B C D || F G H I • -------------------------------------- • 0 0 0 || 0 0 0 1 • 0 0 1 || 1 0 1 0 • 0 1 0 || 0 1 1 0 • 0 1 1 || 1 0 0 1 • 1 0 0 || 0 0 1 1 • 1 0 1 || 0 1 0 1 • 1 1 0 || 1 1 0 0 • 1 1 1 || 1 1 1 0 KEY ELEMENTS OF MD5

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

  8. SHA-1 COMPRESSION FUNCTION

  9. ELEMENTARY SHA OPERATION

  10. B C D || f0..19 f20..39 f40..59 f60..79 • ---------------------------------------------------------------------------- • 0 0 0 | 0 0 0 0 • 0 0 1 | 1 1 0 1 • 0 1 0 | 0 1 0 1 • 0 1 1 | 1 0 1 0 • 0 0 | 0 1 0 1 • 1 0 1 | 0 0 1 0 • 1 0 | 1 0 1 0 • 1 1 1 | 1 1 1 1 TRUTH TABLE for ft – SHA-1

  11. CREATION OF 80-WORD I/P

  12. MD5 message digest – 128 bits SHA-1 message digest – 160 bits Find two messages with same digest: MD5 – 264 operations SHA-1 - 280 operations Comparison: MD5 vs SHA1

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

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

  15. RIPEMD – 160COMPRESSION FUNCTION

  16. RIPEMD – 160ELEMENTARY OPERATION

  17. Tables 12.5 – 12.9 RIPEMD – 160 - data

  18. Table 12.8 - comparison Table 12.9 - relative performance HASH FUNCTIONS - comparisons

  19. 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) HMAC – a MAC from a HASH

  20. HMAC STRUCTURE

  21. EFFICIENT IMPLEMENTATION of HMAC

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