алгоритм гешування

криптографічна геш-функція

<p>A function that maps a bit string of arbitrary length to a fixed-length bit string. Depending upon the relying application, the security strength that can be supported by a hash function is typically measured by the extent to which it possesses one or more of the following properties</p><p>1. (Collision resistance) It is computationally infeasible to find any two distinct inputs that map to the same output.</p><p>2. (Preimage resistance) Given a randomly chosen target output, it is computationally infeasible to find any input that maps to that output. (This property is called the one-way property.)</p><p>3. (Second preimage resistance) Given one input value, it is computationally infeasible to find a second (distinct) input value that maps to the same output as the first value.</p><p>This Recommendation uses the strength of the preimage resistance of a hash function as a contributing factor when determining the security strength provided by a key-derivation method.</p><p>Approved hash functions are specified in [FIPS 180] and [FIPS 202].</p>

NIST SP 800-106