From: Kent Briggs <72124.3234@compuserve.com>
Date: Sun, 25 Feb 1996 03:26:33 +0800
To: cypherpunks@toad.com
Subject: Re: Puffer 2.0 Released
Message-ID: <199602240101.UAA29346@bb.hks.net>
MIME-Version: 1.0
Content-Type: text/plain


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>>>>>
Is PC1 a stream cipher implemented in a "clean room", by reference to an
abstract specification of the algorithm implied by the Alleged-RC4 source
code, that interoperates with RC4-40 ?
<<<<<

Yes, I wrote it in Pascal (Delphi) using only the English pseudo-code 
provided by Bruce Schneier in the 2nd edition of Applied Cryptography.  
I call my implementation PC1 to avoid any possible trademark hassles.  
The sample RC4 vector that the State Dept. sent me for my Commodity 
Jurisdiction request showed that my implementation is correct.  And
of course, there are no patents to worry about and I'm not under any
non-disclosure agreements.

RSADSI's government-sponsored monopoly on 40-bit exportable encryption
is over. 

I generate a key by combining a 40-bit pseudo-random salt with 40-bits
of secret key material.  The secret key material is the lower 40-bits of
a salted pass-phrase after running through a SHA-1 hash.

All the specs and file formats are included with the documentation.

Kent

Puffer is available at http://execpc.com/~kbriggs


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