[CI] Re: Finding collision resistant hash functions

[Sarad AV]

hi,


--- Mike Rosing <eresrch at eskimo.com> wrote:
>It can't be collision free if the number of input
> bits exceeds the number
> of output bits.  Think about it, it should be
> obvious!

Yes,the pigeon hole principle but that was not what i
meant.
Lets say we are using SHA-1 and i hash 2^80
messages.What I am looking for is a compression
function such that the chances of collision in the
message digest obtained by hashing these 2^80 messages
is collision free or very low probability of
collision.How do we make such a compression function?

I am not hashing more than 2^160 to get the collisions
as you had suggested.


Regards Sarath. 



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