Plain Text
ciphertext - format of data after it's encrypted
RPT-13 - rotation cipher - A common rotation cipher is Rot-13, frequently used to conceal information on bulletin board systems such as Usenet
Vigenere Table - Multi-alphabet - Alphabet is repeated 26 times to form a matrix, called the VigenèreSquare
Symmetric vs Asymmetric
Symmetric - very fast - same key for encryption and decrypt - often referred to as shared key - Key Management is biggest concern
Asymmetric - uses two key system - Key pair - public and private keys
Hashing - Mathematical algorithm applied to a file before and after transmission - if anything changes during transmission the hash will change
MD5, SHA1, SHA2
ECC Elliptic Curve Cryptopgraphy - Asymmetric encryption uses algebraic structure of elliptic curves - Strong encryption using smaller key size
Strong vs weak ciphers - strong ciphers can become weaker as computer power increases - current strong ciphers: AES, 3DES, TwoFish - Weak ciphers - deprecated: WEP, WPA
Digital Signature - Asymmetric encryption using public key/ private key (PKI)
Entropy - randomness collected by system Confusion - each character of ciphertext depends on several parts of the key Diffusion - dissipating the statistical structure of the plaintext
Block v. Stream - both are symmetric Block cipher - encrypts in chunks (blocks) of date Stream cipher - encrypts one bit at a time