mzHash32

Strong, fast, simple, non-cryptography hash function

public static int mzHash32(final byte[] data, int start, int length, int seed) {
	int hash = 0x95DE1432 ^ seed;
	for(int i = 0; i < length; i++)
		hash = (0xA8657C5B * (i + data[start + i])) ^ (hash << 2) ^ (hash >>> 2);
	return hash;
}

Uniform distribution of hash values (diffusion)

It has an absolutely uniform, chaotic distribution of hash values independent of the number, length and type of input values.
It also has a good Avalanche Effect property: even a minimal differences (1 bit) of input values produces very different hash values.

java.lang.String.hashCode(): suboptimal dispersion

Hash funtion: java.lang.String.hashCode()
Source file: words_en.txt
Distinct words: 65503
Collisions: 118 (expected 0.4994)
Monte Carlo Pi: 3.251076 (error 3.48%)

mzHash32(): optimal dispersion

Hash funtion: mzHash32()
Source file: words_en.txt
Distinct words: 65503
Collisions: 0 (expected 0.4994)
Monte Carlo Pi: 3.142346 (error 0.02%)

Minimum number of collisions

mzHash32 produces a very low number of collisions for each reasonably large number of distinct values; it is close to the collisions number of a Universal Hash Function.
The number is given by the formula n-m*(1-((m-1)/m)^n) where n is the number of input values, m is the number of all possible hash values (2^32 or 2^64).

Number of collisions for string inputs

Data input	#Vaues	#Expected Collisions	mzHash	Murmur3	XX
File words_en.txt	65,503	0	0	0	0
File words_es.txt	74,571	1	0	2	0
File words_latin.txt	80,007	1	1	1	1
File words_it.txt	117,558	2	0	0	2
File words_en_es_it_latin.txt	315,198	12	9	9	9
File words_and_numbers.txt	429,187	21	17	20	19
File first_million_primes.txt	1,000,000	116	109	118	85
File random_64_signed_nums.txt	1,000,000	116	105	110	143
Numbers in english from "zero" to "nine million nine hundred ninety-nine thousand nine hundred ninety-nine"	10,000,000	11,633	11,735	11,672	11,474
File rockyou.txt dictionary of common passwords	14,442,069	24,254	168,561	168,887	168,563
Numbers in english from "five hundred thirty-nine billion three hundred twenty million seven hundred one thousand four hundred eighty-three" to "five hundred thirty-nine billion four hundred twenty million seven hundred one thousand four hundred eighty-two"	100,000,000	1,155,171	1,152,258	1,155,029	1,154,135
Number as strings from "1234567890123456789" to "1234567890223456788"	100,000,000	1,155,171	1,154,640	1,155,789	808,693
Strings from "abcdefg1234567890 123456789hijklmn" to "abcdefg1234567890 223456788hijklmn"	100,000,000	1,155,171	1,125,889	1,152,600	1,037,151
Numbers as strings from "0" to "999999999"	1,000,000,000	107,882,641	107,105,249	107,822,463	110,287,893
Numbers as strings from "aaaa0aaaa" to "aaaa1999999999aaaa"	2,000,000,000	401,068,994	400,972,197	401,043,716	391,119,332
Hex numbers as string from "0" to "7FFFFFFE"	2,147,483,647	457,545,699	457,447,653	457,465,265	460,825,702

Number of collisions for binary inputs

Data input	#Vaues	#Expected Collisions	mzHash	Murmur3	XX
Binary 32 bytes random	100,000	1	1	0	2
Binary 40 bytes [b,b,b,b,b,b,b,b,b,b] b from FF676980 to FFFFFFFF	10,000,000	11,633	11,295	11,695	11,846
Binary 24 bytes [b,b,b,b,b,b], b from 00000000 to 05F5E0FF	100,000,000	1,155,171	1,155,140	1,154,653	1,411,483
Binary 24 bytes [b,b*3,b*5,b*7,b*11,b*13], b from 00000000 to 05F5E0FF	100,000,000	1,155,171	1,154,633	1,154,542	1,160,003
Binary 24 bytes [b,b,b,b,b,b], b from 00000000 to 05F5E0FF	1,000,000,000	107,882,641	107,908,082	107,880,319	113,834,210

Speed

Vulnerability

MzHash32, like most non-cryptographic functions, is non-secure because it is not specifically designed to be difficult to reverse by an adversary, making it unsuitable for cryptographic purposes. Its use is instead recommended in all other contexts where hash functions are used.
Like other non-cryptographic functions, its security depends on the secrecy of the possibly used seed.

Portability

It is minimalist, elegant, straightforward and can be easily written in virtually any programming language. It produces the same result with x86 and x64 (or different) platforms. Currently C and Java versions are available.

Conclusion

MzHash32 demonstrates to have an excellet quality of the dispersion, close to an ideal Universal Hash Function. It is simple, portable and produces same results in all platform (x86 and x64). On the other hand it is slower than XX and Murmur3. If the goal is the quality of the dispersion and have the same result on x86 and x64 platforms, mzHash32 is certainly the function to choose!