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Chapter 14. VPNs and Cryptology > Cryptographic Hashes
Cryptographic Hashes
Cryptographic hashes are based on one-way functions that are used for integrity assurance. They hash arbitrary data into a fixed-length digest known as a fingerprint.
Hashing alone does not add security to the message. It only prevents the message from being changed accidentally, such as by a communication error.
Well-Known Hashing Algorithms
Hash-Based Message Authentication Codes
Hash-based Message Authentication Codes (HMAC) use existing hash functions and add a secret key as input to the hash function to provide integrity assurance and authentication. Only parties who have access to that secret key can compute the digest of an HMAC function.