The language of cryptography @→Alice's @学Bob's KA encryption decryption key key plaintext encryption ciphertext decryption plaintext algorithm algorithm m:plaintext message KA(m):ciphertext,encrypted with key KA m KB(KA(m)) Security:8-9 The language of cryptography m: plaintext message KA (m): ciphertext, encrypted with key KA m = KB (KA (m)) plaintext ciphertext plaintext KA encryption algorithm decryption algorithm Alice’s encryption key Bob’s decryption key KB Security: 8- 9