Definition
Symmetric Encryption Scheme
A symmetric encryption scheme with a key space
, message space , and ciphertext space is a triple of algorithms: where:
- The key generation algorithm
takes no input (arity 0) and returns a randomly selected key . - The encryption algorithm
takes a key and a message , and produces a ciphertext :
- The decryption algorithm
takes a key and a ciphertext , and produces a plaintext , or an error: