A 2011 attack by Marc Stevens can produce hash collisions with a complexity between 260.3 and 265.3 operations.[1] The first public collision was published on 23 February 2017.[2] SHA-1 is prone to length extension attacks. In cryptography, SHA-1 (Secure Hash Algorithm 1) is a hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest – typically rende