Aquél basado en un algoritmo irreversible. Se emplea, principalmente, para almacenar de manera segura contraseñas de usuarios de un sistema. Últimamente se usa también  para la generación de contraseñas desechables. [Ribagorda:1997]

(I) Irreversible transformation of plain text to cipher text, such that the plain text cannot be recovered from the cipher text by other than exhaustive procedures even if the cryptographic key is known. (See: brute force, encryption.) [RFC4949:2007]

Irreversible transformation of plaintext to cipher text, such that the plaintext cannot be recovered from the cipher text by other than exhaustive procedures even if the cryptographic key is known.