Null encryption

This article is about the configuration option in modern communication systems. For the classical encryption method, see Null cipher.

In modern cryptography, null encryption (or selecting null cipher or NONE cipher) is choosing not to use encryption in a system where various encryption options are offered. When this option is used, the text is the same before and after encryption, which can be practical for testing/debugging, or authentication-only communication. In mathematics such a function is known as the identity function.

Examples of this are the "eNULL" and "aNULL" cipher suite in OpenSSL,^[1] and the "NULL Encryption Algorithm" in IPSec.^[2]

See also

• RFC 2410: "The NULL Encryption Algorithm and Its Use With IPsec"