What is a good hashing algorithm for seeding a prng with a string?

Question

I am looking for a hashing algorithm that produces a 31/32 bit signed/unsigned integer as a digest for a utf8 string with the purpose of using the output for seeding a prng, such as a Park-Miller-Carta LCG or a Mersenne-Twister.

I have looked into FNV1 and FNV1a, but they provide very close values for similar strings differing in their last character; I would like to have a low collision hash that radically changes upon minimal modifications on the input string. Performance is not an issue.

My current approach consists in a dirty LCG that uses character codes and a prime number as multipliers:

a = 524287;
for ( i = 0; i < n; i ++ )
a = ( a * string.charCodeAt ( i ) * 16807 + 524287 ) % 2147483647;

Please let me know of any better alternatives.

Answer 1

If you're generating 32-bit value, consider using classic CRC32. FNV is suposed to be fast alternative to CRC, and you're saying, that performance is not an issue.

Answer 2

Use SHA-2

It is the best/latest hashing algorithm out there. It is always advisable to go with standard algorithms.

Answer 3

Any cryptographically strong hash will have the properties you want, but generate more bits, but simple truncation of the result to 32 bits would be fine. I presume cryptographic strength is not an actual requirement so that flawed (but widely used) hash schemes like MD5 would be adequate - and readily available in many libraries.