substitution

noun 0.740

substitution reaction

noun 0.674

substitute

noun 0.635

cipher

noun 0.626

block cipher

noun 0.600

ciphering

noun 0.595

cryptogram

noun 0.582

substitutivity

noun 0.571

substitutable

noun 0.568

cryptography

noun 0.564

penal substitution

noun 0.564

codebreaking

noun 0.564

ciphertext

noun 0.555

codeword

noun 0.541

stream cipher

noun 0.540

nucleophilic substitution

noun 0.529

substitutability

noun 0.524

cryptology

noun 0.522

cryptologist

noun 0.519

cryptographer

noun 0.517

cryptosystem

noun 0.512

cryptanalysis

noun 0.508

decryption

noun 0.508

electrophilic substitution

noun 0.507

anagram

noun 0.506

transposition

noun 0.505