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Question, instead of using two hash functions, why not use just a single function but use a = hash(foo) and b = hash(foo+"something")? A well distributed hash f

Question, instead of using two hash functions, why not use just a single function but use a = hash(foo) and b = hash(foo+"something")? A well distributed hash function should give drastically different results for a and b for different values of foo, which is what we want, correct?

kurige 13y ago
It's standard to have at least two hashing functions. You can then simulate having x hash functions simply by combining those two.[1] But, your question is entirely valid and I'm not really sure why you couldn't do that. It might simply be that the kinds of hash functions used in bloom filters (non-cryptographic) are not well distributed. [1]: http://citeseer.ist.psu.edu/viewdoc/download;jsessionid=4060353E67A356EF9528D2C57C064F5A?doi=10.1.1.152.579&rep=rep1&type=pdf http://citeseer.ist.psu.edu/viewdoc/download;jsessionid=4060...
- makmanalp 13y ago
  Fascinating, thank you! I'll take a look at the paper when I get back home.
natch 13y ago
That's what I do, and it works just fine. I was going to raise this point but you beat me to it.