Cipher

In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption.

Description

A cipher uses an algorithm: a series of well-defined steps that can be followed as a procedure.

To encipher or encode is to convert information into cipher or code.

Cipher versus code

In non-technical usage, a 'cipher' is the same thing as a 'code'; however, the concepts are distinct in cryptography.

In classical cryptography, ciphers were distinguished from codes.

Codes generally substitute different length strings of characters in the output, while ciphers generally substitute the same number of characters as are input.

There are exceptions and some cipher systems may use slightly more, or fewer, characters when output versus the number that were input.

See also

• Algorithm
• Ciphertext
• Cryptography
• Encode
• Encryption
• Decryption
• One-time pad
• Plaintext

External links

• Cipher @ Wikipedia