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...

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

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

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

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

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

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

The Aristocrat Cipher is a type of monoalphabetic substitution cipher in which plaintext is replaced with ciphertext and encoded into assorted letters...

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...

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

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...

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

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

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...

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

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

In classical cryptography, the running key cipher is a type of polyalphabetic substitution cipher in which a text, typically from a book, is used to provide...

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

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

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...

cryptography, a block cipher is a deterministic algorithm that operates on fixed-length groups of bits, called blocks. Block ciphers are the elementary building...

provide him with an important clue—he realises that they form a substitution cipher and cracks the code by frequency analysis. The last of the messages...

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

resistant to cryptanalysis. The product cipher combines a sequence of simple transformations such as substitution (S-box), permutation (P-box), and modular...

Although ciphers can be confusion-only (substitution cipher, one-time pad) or diffusion-only (transposition cipher), any "reasonable" block cipher uses both...

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

Vigenère cipher is therefore a special case of a polyalphabetic substitution. First described by Giovan Battista Bellaso in 1553, the cipher is easy to...

(or secret decoder) is a device that allows one to decode a simple substitution cipher—or to encrypt a message by working in the opposite direction. As...