Murmur Example

[Back] While hashing methods such as MD5 and SHA-1 use cryto methods, the Murmur and FNV hashes uses a non-cryptographic hash function. The Murmur hash, designed by Austin Appleby, uses a non-cryptographic hash function. This can be used for general hash-based lookups. It has a good performance compared with other hashing methods, and generally provide a good balance between performance and CPU utilization. Also it performs well in terms of hash collisions. [Theory]

FNV (Fowler–Noll–Vo) is a 64-bit non-cryptographic hash function developed by Glenn Fowler, Landon Curt Noll, and Phong Vo. There are two main versions, of which 1a is the most up-to-date version.

The results are then:

Murmur (Ver 3) - 128-bit	6c1b07bc7bbc4be347939ac4a93c437a
Murmur (Ver 2) - 64-bit	E332EA633D4BBF75
FNV - 64-bit	A8B2F3117DE37ACE
FNV1a - 64-bit	F3F9B7F5E7E47110

Examples

Try "The quick brown fox jumps over the lazy dog". Try!, which should give a Murmur hash of: 0x6c1b07bc7bbc4be347939ac4a93c437a Check and an FNV hash of A8B2F3117DE37ACE and F3F9B7F5E7E47110 for FNV1a
Try "The quick brown fox jumps over the lazy dog.". Try!, which should give a Murmur hash of: 0xc902e99e1f4899cde7b68789a3a15d69 and an FNV hash of 8B8DD4B8E989AC24 and 75C4D4D9092C6C5A for FNV1a Check

Code

I have used Hashlib for Version 2, and custom code for Version 3:


using Hashlib;

byte[] key = new byte[4];
key[0] = 0; key[1] = 0; key[2] = 0; key[3]=0;

var hash1 = HashFactory.Hash128.CreateMurmur3_128();
hash1.Key = key;
byte[] res1 = hash1.ComputeString(word, Encoding.ASCII).GetBytes();

ViewData["mur"] = ByteArrayToHexString(res1);

var hash2 = HashFactory.Hash64.CreateMurmur2();
var crc64 = hash2.ComputeString(word, Encoding.ASCII).GetULong();

ViewData["mur2"] = longToHex(crc64);

var hash3 = HashFactory.Hash64.CreateFNV();
crc64 = hash3.ComputeString(word, Encoding.ASCII).GetULong();

ViewData["mur3"] = longToHex(crc64);

var hash4 = HashFactory.Hash64.CreateFNV1a();
crc64 = hash4.ComputeString(word, Encoding.ASCII).GetULong();

ViewData["mur4"] = longToHex(crc64);
       

public string longToHex(ulong l)
{

  return String.Format("{0:X}", l);

}

We can also check using the smhasher library in Python:

$ cat sm.py
import smhasher
msg="The quick brown fox jumps over the lazy dog"
res=smhasher.murmur3_x64_128(msg,0)
print('%s\n  %d\n  %s\n' % (msg, res, hex(res)))

msg="The quick brown fox jumps over the lazy dog"
res=smhasher.murmur3_x64_64(msg,0)
print('%s\n  %d\n  %s\n' % (msg, res, hex(res)))

root@bills-mbp:~$ python sm.py
The quick brown fox jumps over the lazy dog
  143696972470007425495137670989352813434
  0x6c1b07bc7bbc4be347939ac4a93c437aL

The quick brown fox jumps over the lazy dog
  7789828486578588643
  0x6c1b07bc7bbc4be3L

Murmur Example

Examples

Code

Presentation