A named algorithm whose defined purpose is securing, encrypting, signing or hashing data. Belongs here: Advanced Encryption Standard Algorithm, RC4 Algorithm and SHA-256 Algorithm, each a defined cryptographic primitive. Does not belong here: a general numerical technique, such as a primality test, that cryptography depends on but that is defined by its own mathematical result rather than by a security purpose, filed under Numerical Algorithm; and the general concept of public key cryptography, filed under the technique-holding concept type.