Re: Why unhashing is not possible?

In article <vtgcj.20006$wy2.11449@edtnps90>,
Unruh <unruh-spam@xxxxxxxxxxxxxx> wrote:

No, a hash is NOT unique. Many many many many inputs give the same hash.
That is the essense of a hash.

http://en.wikipedia.org/wiki/Hash_function

A hash function [1] is a reproducible method of turning some kind
of data into a (relatively) small number that may serve as a
digital "fingerprint" of the data.


There is no requirement there that the output cannot be unique
if the input is limited.

For example, if you were to write a compiler or interpreter for
a language with a fixed set of keywords, then the strings that
were the keywords could be hashed to produce a table offset
used for dealing with that particular keyword -- instead of doing
a string search or B-Tree or 2-3 Tree traversal to determine
the entry.
.