polyalphabetic substitution

[ pol-ee-al-fuh-bet-ik suhb-sti-too-shuhn, ‐tyoo-shuhn, pol-ee- ]

nounCryptography.
  1. 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.

Origin of polyalphabetic substitution

1
1935–40; poly- + alphabetic

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024