32.One way functions sha algorithm. Sha-256, sha-384, and sha-512.

Secure Hash Algorithm (SHA)

The Secure Hash Algorithm (SHA) for use with the Digital Signature Standard.According to the Federal Register. This proposed standard specified a Secure Hash Algorithm (SHA) for use with the proposed Digital Signature Standard. Additionally, for applications not requiring a digital signature, the SHA is to be used whenever a secure hash algorithm is required for Federal applications.

Description of SHA

First, the message is padded to make it a multiple of 512 bits long. Padding is exactly the same as in MD5: First append a one, then as many zeros as necessary to make it 64 bits short of a multiple of 512, and finally a 64-bit representation of the length of the message before padding.

SHA-256

SHA-512

SHA-384

SHA-384 is defined in the exact same manner as SHA-512 with the following two

exceptions:

1. The initial hash value H(0) is based on the fractional parts of the square roots of the ninth through sixteenth primes.

2. The final 384-bit hash is obtained by truncating the SHA-512-based hash output to its left-most 384 bits.

It is possible to use a symmetric block cipher algorithm as a one-way hash function. The idea is that if the block algorithm is secure, then the one-way hash function will also be secure.

The general scheme is as follows

1. Security methods. Kerckhoff’s Principle

2. Tasks of cryptography

3. Attack. . Type of attacks. Threats to computer systems. Threat Models. Threat Trees

4. Basic methods of encryption. Classification of encryption methods. Examples of simple methods.

5. Caesar’s cipher generalized. Other monoalphabetic ciphers. The problems.

6. One-Time Pad cipher.

7. Polyalphabetic ciphers. Vigenere Tableau.

9. New standard. AES. Mathematical basic. Algorithm. Key Schedule

10. Symmetric cryptosystem. DES

11. Symmetric cryptosystem. 3DES

12. Symmetric cryptosystem. AES

13. Block Cipher Modes

14. Stream Ciphers. PRG

15. Stream Ciphers. RC4

16. Public key crypto. RSA

17. Public key crypto. Diffie-Hellman

18. Linear Cryptoanalysis. Example

19. Differential Cryptoanalysis. Example

20. Protocols. Definitions. Rules of communication. Types of protocols. Problems.

21. Secure Protocols. Three types of Protocol

22. Secure Elections. Simplistic Protocol #1,2

23. Secure Elections. Voting with Blind Signatures

24. Secure Elections. Election with two organization

25. Digital Cash Protocol

26. Key management.. Certification problem. Certificate

27. Authority. X.509. Certificate Hierarchy

28. PGP. Key Management in PGP. PGP’s Web of Trust. IDEA. Key Schedule. Standard ANSI X9.17. Working with PGP

29. Protocols. Digital Cash. Examples. Key management

30. One way functions. Properties. Collision-resistance. Example.

31. One way functions MD5 algorithm.

32. One way functions SHA algorithm. SHA-256, SHA-384, and SHA-512.

33. One way functions. Using symmetric algorithms