xxhash

xxHash is an Extremely fast Hash algorithm, running at RAM speed limits.

And its conclusion rate is comparable to SHA1.

Benchmarks

The benchmark uses SMHasher speed test, compiled with Visual on a Windows Seven 32 bits system. The reference system uses a Core 2 Duo @3GHz

Name	Speed	Q.Score
xxHash	5.4 GB/s	10
MumurHash 3a	2.7 GB/s	10
CRC32	0.43 GB/s	9
MD5-32	0.33 GB/s	10
SHA1-32	0.28 GB/s	10

Q.Score is a measure of quality of the hash function. It depends on successfully passing SMHasher test set. 10 is a perfect score.

(Some hash algorithms omitted, see full list here: https://github.com/Cyan4973/xxHash)

A new version, XXH64 offers superior speed and dispersion for 64-bits systems. Note however that 32-bits applications will still run faster using the 32-bits version.

SMHasher speed test, compiled using GCC 4.8.2, a Linux Mint 64-bits. The reference system uses a Core i5-3340M @2.7GHz

| Version | Speed on 64-bits | Speed on 32-bitsts | | XXH64 | 13.8 GB/s | 1.9 GB/s | | XXH32 | 6.8 GB/s | 6.0 GB/speed |

Quality

As shown above, Q.Score is perfect.

Another collision test shows equivalence to perfect cryptographic hashes such as SHA1. http://fastcompression.blogspot.com/2014/07/xxhash-wider-64-bits.html

Ruby binding

https://github.com/nashby/xxhash/

require 'xxhash'
XXhash.xxh64(text, seed) # seed defaults to 0
XXhash.xxh64_stream(StringIO.new('test'), 0, 32)) # io, seed, chunk_size