1. Cryptography
   1. Definition
      1. Study of message secrecy
   2. Goals
      1. Confidentiality
         1. Keep the content of information from all but those authorized
      2. Data integrity
         1. Addresses the unauthorized alteration of data
      3. Authentication
         1. Identification of both entities and information itself
      4. Non-repudiation
         1. Verified that the sender and the recipient were sent or received the message as claimed
   3. Type
      1. Classical cryptography
         1. Sumerians
            1. Cuneiform writing
         2. Egyptians
            1. Hieroglyphic writing
         3. Phoenicians
            1. Alphabets
         4. Hebrew
            1. Monoalphabetic substitution ciphers
         5. Spartan
            1. Scytale
         6. Herodotus
            1. Tatoo on shaved head
         7. Notable Roman
            1. Caeser cipher
         8. India
            1. Karma Sutra
         9. China
            1. Six Strategies
      2. Modern cryptography
         1. Cryptographic mathematics
            1. Binary mathematics
            2. Modulo function
            3. Chinese remainder theorem
            4. One-way functions
            5. Easy to compute, hard to invert
            6. e.g. MD5, SHA-1
            7. Confusion
            8. Relationship between the plaintext and the key is complicated
            9. Diffusion
            10. A change in the plaintext results in multiple changes spread out throughout the ciphertext
         2. Components
            1. Codes
            2. Cryptographic systems of symbols that represent words or phrases
            3. Ciphers
            4. Hide the true meaning of a message
            5. Type
            6. Transposition
            7. Substitution
            8. One-time pad
            9. Perfectly random
            10. Secure generation and exchange
            11. Careful treatment
         3. Type
            1. Symmetric
            2. The way to encrypt and decrypt is the same
            3. Algorithm
            4. Data Encryption Standard
            5. 1973-74, Lucifer by IBM
            6. 1977, published by US gov
            7. 64-bit blocks of cipher text, 56 bits long key
            8. Modes
            9. ECB, CBC, CFB, OFB
            10. Triple DES
            11. 168-bits (56x3)
            12. IDEA
            13. 128-bit keys (8 rounds encryption)
            14. Blowfish
            15. Open source
            16. Variable-length keys
            17. 32-bits
            18. 448-bits
            19. Skipjack
            20. Mainly use in ATM machine
            21. 64-bit blocks of cipher text, 80 bits long key
            22. Advanced Encryption Standard (1997, aka Rijndael algorithm)
            23. Announced by NIST
            24. 128-bit blocks of cipher text
            25. 128-bit keys (9 rounds encryption)
            26. 192-bit keys (11 rounds encryption)
            27. 256-bit keys (13 rounds encryption)
            28. 3 layers of transformation
            29. Linear Mix
            30. Nonlinear
            31. Key addition
            32. PGP
            33. Use to secure email
            34. CAST 128-bit encryption/ decryption algorithm
            35. SHA-1 hash function
            36. Asymmetric (aka Diffie-Hellman Key Exchange)
            37. Two keys are used and work together in such a way that plain text encrypted with the one key can only be decrypted with the other
            38. RSA (1977)
            39. By Ron Rivest, Adi Shamir, and Leonard Adelman
            40. 768, 1024, 2048-bits of key
         4. Key length
            1. Considerations
            2. Competitive advantage
            3. Sensitivity of data
            4. Moore's law
            5. Governance
2. Overview
3. Cryptanalysis
   1. Definition
      1. Study of methods for obtaining the meaning of encrypted information
   2. Classical
      1. Method: Frequency attack
      2. Relies as much on linguistic knowledge as it does on statistics
      3. Stages
         1. Cipher text-only
         2. Known-plaintext
         3. Chosen-plaintext
         4. Adaptive chosen-plaintext
         5. Related-key attack
   3. Modern
      1. Mechanic
         1. Enigma
         2. Alan Turing
      2. Analysis attack
      3. Statistics attack
      4. Bribery
      5. Physical attack
      6. Social engineering
4. Steganography
   1. Definition
      1. Hidden writing
   2. Goals
      1. Hide the secret information within the container file
      2. Mask the secret information behind the container file
   3. Types
      1. Least Significant Byte
      2. Injection
   4. Printer steganography
5. Steganalysis
   1. Definition
      1. Detection of steganographically encoded packages
   2. Detection
      1. Benford's law
         1. The values of real-world measurements are often distributed logarithmically, thus the logarithm of this set of measurements is generally distributed uniformly
6. Public Key Infrastructure
   1. Provide communicating parties with the assurance
   2. Certificate Authorities
      1. Issuing a Certificate
      2. Manage a Certificate
      3. Distribute a Certificate
      4. Key Management
      5. Key Exchange
      6. Key revoke
   3. Kinds of certificate
      1. Class 1
         1. Individuals
      2. Class 2
         1. Organizations
      3. Class 3
         1. Servers
         2. Softwares
      4. Class 4
         1. Online business transactions
      5. Class 5
         1. Private organizations
         2. Governments