One-Way Hash Primitives

Hash functions are used in cryptography with digital signatures and for ensuring data integrity.

When used with digital signatures, a publicly available hash function hashes the message and signs the resulting hash value. The party who receives the message can then hash the message and check if the block size is authentic for the given hash value.

Hash functions are also referred to as “message digests” and “one-way encryption functions”. Both terms are appropriate since hash algorithms do not have a key like symmetric and asymmetric algorithms and you can recover neither the length nor the contents of the plaintext message from the ciphertext.

To ensure data integrity, hash functions are used to compute the hash value that corresponds to a particular input. Then, if necessary, you can check if the input data has remained unmodified; you can re-compute the hash value again using the available input and compare it to the original hash value.

The Hash Functions section describes functions that implement the following hash algorithms for streaming messages: MD5 [RFC 1321] , SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512 [FIPS PUB 180-2]. These algorithms are widely used in enterprise applications nowadays.

Subsequent sections describe Generalized Hash Functions for Non-Streaming Messages, which apply hash algorithms to entire (non-streaming) messages, and Mask Generation Functions, whose algorithms are often based on hash computations.

Each of the above algorithms is implemented as a set of primitive functions.

The full list of Intel® Integrated Performance Primitives (Intel® IPP) Hash Primitive Functions is given in Table “One-way Hash Primitive Functions”.

• Hash Functions
  
• Generalized Hash Functions for Non-Streaming Messages
  
• Mask Generation Functions
  

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