Modern CyphersLn Lou2014.8
Ln Lou 2014.8 Modern Cyphers
O.Security SystemKeyPlainTextCipherTextEncryption(K×P→C)Decryption(K×C-P)
0. Security System • Key • Plain Text • Cipher Text Encryption (K × P → C) Decryption (K × C → P)
1. Symmetric Key Algorithm1.1StreamCyphers1.2BlockCyphers
1. Symmetric Key Algorithm 1.1 Stream Cyphers 1.2 Block Cyphers
1.1 Stream cyphersRC4 (WEP,SSL)Salsa20/12
1.1 Stream cyphers • RC4 (WEP, SSL) • Salsa20/12
One-timePadlen(m) == len(c) == len(k)D(k, m) = k ④mE(k, c) = k ④
One-time Pad len(m) == len(c) == len(k) D(k, m) = k ⊕ m E(k, c) = k ⊕ c