Affine transformation

Caesar cipher

characteristic frequency (of a letter)

cipher

ciphertext

cipher sequence

code

complete set of residues

completing the plain component

congruence, congruent

cryptanalysis

cryptogram

cryptography

cryptology

decimated alphabet

decimation

decipher

decrypt

direct standard alphaabet

encipher

encrypt

general system

linear (congruential) transformation

modulo, mod

modulus

monoalphabetic (substitution) cipher

monographic frequency distribution

multiplicative inverse, reciprocal

plain sequence

plaintext

residue

specific key

substitution cipher

Vigenere tableau, Vigenere square