1. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Security

2. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Security Topics

3. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Cryptography

4. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Cryptography components

5. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Encryption and decryption

6. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 In cryptography, the encryption/decryption algorithms are public; the keys are secret. Note:

7. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Symmetric-Key Cryptography Traditional Cipher Block Cipher Operation Modes

8. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Symmetric-key cryptography

9. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 In symmetric-key cryptography, the same key is used by the sender (for encryption) and the receiver (for decryption). The key is shared. Note:

10. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 In symmetric-key cryptography, the same key is used in both directions. Note:

11. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Symmetric-key cryptography is often used for long messages. Note:

12. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Caesar cipher

13. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Example of monoalphabetic substitution

14. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 In monoalphabetic substitution, the relationship between a character in the plaintext to the character in the ciphertext is always one-to-one. Note:

15. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Vigenere cipher

16. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 In polyalphabetic substitution, the relationship between a character in the plaintext and a character in the ciphertext is one-to-many. Note:

17. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Transpositional cipher

18. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Block cipher

19. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 P-box

20. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 S-box

21. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Product block

22. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 DES

23. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 General scheme of DES

24. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Iteration block

25. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Triple DES

26. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 The DES cipher uses the same concept as the Caesar cipher, but the encryption/decryption algorithm is much more complex due to the sixteen 48-bit keys derived from a 56-bit key. Note:

27. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 ECB mode Electronic Code Book Mode

28. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 CBC mode Cipher Block Chaining Mode

29. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 CFM Cipher Feedback Mode

30. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 CSM Stream Cipher Mode

31. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Cryptanalysis Some common symmetric-key cryptographic algorithms.

32. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Public-Key Cryptography RSA Choosing Public and Private Keys

33. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Public-key cryptography

34. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Public-key algorithms are more efficient for short messages. Note:

35. McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 RSA Public Key 5, 119 Private Key 77, 199