[18073] in cryptography@c2.net mail archive
Re: Query about hash function capability
daemon@ATHENA.MIT.EDU (Ian Clelland)
Thu Aug 4 16:25:32 2005
X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Thu, 04 Aug 2005 11:37:44 -0700
From: Ian Clelland <ian@veryfresh.com>
In-reply-to: <42F183B7.6090606@partow.net>
To: cryptography@metzdowd.com
On Aug 3, 2005, at 7:55 PM, Arash Partow wrote:
> My question relates to hash functions in general and not specifically
> cryptographic hashes. I was wondering if there exists a group of hash
> function(s) that will return an identical result for sequentially
> similar yet rotate/shift wise dissimilar input:
>
> ie: input1 : abcdefg -> h(abcdefg) = 123
> input2 : gabcdef -> h(gabcdef) = 123
> input3 : fgabcde -> h(fgabcde) = 123
>
> Here a,b,c,d,e,f,g represent symbols (ie: groups of bits with
> equivalent
> group sizes etc...)
Why not just include a canonicalization step at the beginning of the
hash that is designed to ignore rotation?
For example, if you can define an ordering on the set of possible
inputs to the hash, then you can rotate any input to the point where it
is the "smallest" (or "largest") that it can be, and then hash *that*
value.
Ian Clelland
<ian@veryfresh.com>
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