COMPUTER NETWORKING

Detailed explanation-1: -A polyalphabetic cipher substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case. The Enigma machine is more complex but is still fundamentally a polyalphabetic substitution cipher.

Detailed explanation-2: -A monoalphabetic cipher uses fixed substitution over the entire message, whereas a polyalphabetic cipher uses a number of substitutions at different positions in the message, where a unit from the plaintext is mapped to one of several possibilities in the ciphertext and vice versa.

Detailed explanation-3: -noun. : polyalphabetic substitution in which the choice of alphabets is limited (as by a key word) compare progressive-alphabet cipher.