polyalphabetic substitution
[pol-ee-al-fuh-bet-ik, pol-ee-]
noun Cryptography.
a system of substitution that mixes together a number of cipher alphabets in a cryptogram so that each plaintext letter is represented by a cipher that repeatedly changes.
Compare monoalphabetic substitution.
Origin of polyalphabetic substitution
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019