Re: How to shorten output of a hash function?

Kristian Gjøsteen <kristiag+news@xxxxxxxxxxxx> wrote:

Simon Johnson <simon.johnson@xxxxxxxxx> wrote:

1) Just use the first N bytes.

For 1: a hash function where the first N bytes are fixed to zero.

Why is having of all zeros a problem? It should be just as hard to
find a collision against a hash of all zeros as it should any other
hash value.

I'm sure you can come up with a collision for the hash function
h:{0,1}* -> {0,1} given by h(x) = 0^n. :-)

Aren't hash functions meant to emulate PRFs? I don't know what you mean
by (^n), but your example doesn't look remotely like a PRF.


Greets,
Ertugrul.


--
nightmare = unsafePerformIO (getWrongWife >>= sex)

.

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