title: Fast hash function with collision possibility near SHA-1
body: <p>I'm using SHA-1 to detect duplicates in a program handling files. It is not required to be cryptographic strong and may be reversible. I found this list of fast hash functions <a href="https://code.google.com/p/xxhash/" rel="nofollow noreferrer">https://code.google.com/p/xxhash/</a> (list has been moved to <a href="https://github.com/Cyan4973/xxHash" rel="nofollow noreferrer">https://github.com/Cyan4973/xxHash</a>)</p>
  <p>What do I choose if I want a faster function and collision on random data near to SHA-1?</p>
  <p>Maybe a 128 bit hash is good enough for file deduplication? (vs 160 bit sha-1)</p>
  <p>In my program the hash is calculated on chuncks from 0 - 512 KB.</p>