[21476] in cryptography@c2.net mail archive

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passphrases with more than 160 bits of entropy

daemon@ATHENA.MIT.EDU (Travis H.)
Tue Mar 21 22:25:42 2006

X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Tue, 21 Mar 2006 14:44:23 -0600
From: "Travis H." <solinym@gmail.com>
To: cryptography@metzdowd.com

Hi,

Does anyone have a good idea on how to OWF passphrases without
reducing them to lower entropy counts?  That is, I've seen systems
which hash the passphrase then use a PRF to expand the result --- I
don't want to do that.  I want to have more than 160 bits of entropy
involved.

I was thinking that one could hash the first block, copy the
intermediate state, finalize it, then continue the intermediate result
with the next block, and finalize that.  Is this safe?  Is there a
better alternative?
--
Security Guru for Hire http://www.lightconsulting.com/~travis/ -><-
GPG fingerprint: 9D3F 395A DAC5 5CCC 9066  151D 0A6B 4098 0C55 1484

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