different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger...

message, so the cipher is classed as a type of monoalphabetic substitution, as opposed to polyalphabetic substitution. The Caesar cipher is named after...

Napoleon cipher, and tic-tac-toe cipher) is a geometric simple substitution cipher, which exchanges letters for symbols which are fragments of a grid...

polyalphabetic cipher is a substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though...

Classical ciphers are often divided into transposition ciphers and substitution ciphers, but there are also concealment ciphers. In a substitution cipher, letters...

Playfair cipher or Playfair square or Wheatstone–Playfair cipher is a manual symmetric encryption technique and was the first literal digram substitution cipher...

between transposition and substitution operations, they are often combined, as in historical ciphers like the ADFGVX cipher or complex high-quality encryption...

ciphers used in the past are sometimes known as classical ciphers. They include simple substitution ciphers (such as ROT13) and transposition ciphers...

Atbash (Hebrew: אתבש; also transliterated Atbaš) is a monoalphabetic substitution cipher originally used to encrypt the Hebrew alphabet. It can be modified...

of ciphers known as polygraphic substitution ciphers. This adds significant strength to the encryption when compared with monographic substitution ciphers...

one of three categories of cipher used in classical cryptography along with substitution ciphers and transposition ciphers. In classical cryptography...

Hill cipher is a polygraphic substitution cipher based on linear algebra. Invented by Lester S. Hill in 1929, it was the first polygraphic cipher in which...

Caesar cipher and one-time pad) Polyalphabetic substitution cipher: a substitution cipher using multiple substitution alphabets (e.g., Vigenère cipher and...

are used: for instance, a cipher in which pairs of letters are substituted is bigraphic. As a concept, polygraphic substitution contrasts with monoalphabetic...

potential to be exploited in a ciphertext-only attack. In a simple substitution cipher, each letter of the plaintext is replaced with another, and any particular...

use either stream ciphers or block ciphers. Stream ciphers encrypt the digits (typically bytes), or letters (in substitution ciphers) of a message one...

The affine cipher is a type of monoalphabetic substitution cipher, where each letter in an alphabet is mapped to its numeric equivalent, encrypted using...

than its content. Baconian ciphers are categorized as both a substitution cipher (in plain code) and a concealment cipher (using the two typefaces). To...

cryptography, an SP-network, or substitution–permutation network (SPN), is a series of linked mathematical operations used in block cipher algorithms such as AES...

music ciphers that utilize homophonic substitution (one-to-many), polyphonic substitution (many-to-one), compound cipher symbols, and/or cipher keys;...

The Enigma machine is a cipher device developed and used in the early- to mid-20th century to protect commercial, diplomatic, and military communication...

of ciphers known as polygraphic substitution ciphers. This adds significant strength to the encryption when compared with monographic substitution ciphers...

This method was used in the second Beale cipher. This variant is more properly called a substitution cipher, specifically a homophonic one. Both methods...

in Sweden, found the cipher to be an encrypted German text. The manuscript is a homophonic cipher that uses a complex substitution code, including symbols...

The Beaufort cipher, created by Sir Francis Beaufort, is a substitution cipher similar to the Vigenère cipher, with a slightly modified enciphering mechanism...

applied cipher-solving computer algorithms to the Dorabella cipher and discovered that it is unlikely to be a monoalphabetic substitution cipher in English...

advance positions, changing the substitution. By this means, a rotor machine produces a complex polyalphabetic substitution cipher, which changes with every...

consistent with the one-time pad being unbreakable. For a simple substitution cipher, the number of possible keys is 26! = 4.0329 × 1026 = 288.4, the...

Frequency analysis relies on a cipher failing to hide these statistics. For example, in a simple substitution cipher (where each letter is simply replaced...

cryptography, an S-box (substitution-box) is a basic component of symmetric key algorithms which performs substitution. In block ciphers, they are typically...