# A CDE Definition

message digest

A fixed number of characters that were generated by a hash function from the contents of a message input. See cryptographic hash function.

cryptographic hash function

An algorithm that transforms a given amount of data (the "message") into a fixed number of digits, known as the "digest," "tag" or "hash." Cryptographic hash functions are a fundamental encryption component in digital signatures, password security, random number generation, message authentication and blockchain architectures.

**One-Way Processing**

Also called a "one-way hash function," the one-way means that it is extremely difficult to turn the digest back into the original message. It is also exceedingly rare that two different message inputs can result in the same digest output.

**Not the Same as Hash Tables**

Cryptographic hashes differ from hash tables. The cryptographic function is designed to process much more quickly and to generate random output. See hash table, HMAC, digital signature, MD5 and SHA.

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