Cryptography

Domain Topics
- Cryptography converts plain text messages or data into unreadable cipher text
- Earlier methods used transposition or substitution ciphers
- Modern methods much more complex
- Mathematical algorithms used to encipher
- Cryptography supports these goals:
-- Confidentiality
-- Authentication
-- Integrity
-- Non-Repudiation
- Two things required to encrypt and decrypt:
-- Algorithm and Key
-- Strength of encryption increases with strength / complexity of algorithm and size of key
* Basics of Cryptography
- Given: Plaintext (P), Encryption (E), Decryption (D), and Ciphertext (C):
-- C=E(P) and,
-- P=D(C)
- Security personnel need to be able to evaluate suitability of cryptosystems based on knowledge of cryptography
- Should understand the terminology and concepts for the CISSP exam, but don't have to be a mathematician!
- Two kinds of algorithms:
-- Symmetric (secret key)
-- Asymmetric (public-private key)