[14743] in cryptography@c2.net mail archive
Re: Protection against offline dictionary attack on static files
daemon@ATHENA.MIT.EDU (Ken Ballou)
Thu Nov 13 21:38:53 2003
X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Wed, 12 Nov 2003 13:29:35 -0500
From: Ken Ballou <ballou@crab.mv.com>
To: cryptography@metzdowd.com
Mail-Followup-To: cryptography@metzdowd.com
In-Reply-To: <3F978143.7070005@ramonsky.com>
On Thu, Oct 23, 2003 at 08:20:35AM +0100, Arcane Jill wrote:
> Hi,
>
> It's possible I may be reinventing the wheel here,
Not really. You've just come down with a bad case of the PBEs. ;-)
Take a look at PKCS #5 (here's a link to version 1.5:
ftp://ftp.rsasecurity.com/pub/pkcs/ascii/pkcs-5.asc). Essentially, it's
the scheme you just described, with provisions for generating more bits
of keying material if the encryption algorithm requires more bits than the
hash algorithm provides. (For instance, imagine AES with a 256 bit key,
but suppose the hash algorithm is SHA-1, which only produces 160 bits
of output.)
- Ken
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