Wiktionary
substitution ciphers
n. (plural of substitution cipher English)
Usage examples of "substitution ciphers".
The codes they were facing were no longer simple substitution ciphers crackable with pencil and graph paper--they were computer-generated hash functions that employed chaos theory and multiple symbolic alphabets to scramble messages into seemingly hopeless randomness.
The codes they were facingwere no longer simple substitution ciphers crackable with penciland graph paper&mdash.
The Hardys told their friends more about solving substitution ciphers, and they all worked diligently for nearly two hours.