Hashes and collisions

Hashes and collisions

Posted Nov 13, 2003 10:47 UTC (Thu) by rjw (guest, #10415)
In reply to: Hashes and collisions by dd9jn
Parent article: An attempt to backdoor the kernel

Erm.

A hash function produces a small fixed number of bits from a large, potentially limitless number of bits.

Just think for one second about that.
Lets take a file on a crappy 32-bit operating system as a limit. And hash it to 160 bits.

How the hell do you think that every one of 2^(2^32) combinations can map to 2^160 combinations uniquely?

Cryptographic hash functions merely make it computationally hard to find a match, and even harder to find a match which contains what you want it to.

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