Block cipher Definition An n-bit block cipher is a function E:Vn×KVn, uch that for each key K∈K E(P; K )is an invertible mapping( the encryption function for k) from vn to Vn, written Ex(P). The inverse mapping is the decryption function, denoted DK(C). p denotes that ciphertext results from encrypting plaintext P under k2 Block cipher Definition An n-bit block cipher is a function E : VnK→Vn , such that for each key K K, E(P;K) is an invertible mapping (the encryption function for K) from Vn to Vn , written EK (P). The inverse mapping is the decryption function, denoted DK (C). P denotes that ciphertext results from encrypting plaintext P under K