From jpetrov@illinois.edu Tue Oct 22 12:30:04 1996
Path: ashpoly!cascade!transat!eunet-fr!teletel!illinois!jpetrov
From: jpetrov@illinois.edu (Joachim Petrov)
Newsgroups: comp.sys.m68k
Subject: WTB/WTT: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1996Oct22.123004.9240@illinois.edu>
Date: Tue, 22 Oct 1996 12:30:04 GMT
Organization: University of Illinois Urbana-Champaign
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Lines: 11

Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.
This indicates socket U14 held a cryptographic S-box lookup table for decrypting the Stardust keystream.

Does anyone have a 27C256 EPROM marked 'MH-U14' or 'ORION-CRYPTO'?

-- 
=== Joachim Petrov ===
Dept of Electrical Engineering, University of Illinois Urbana-Champaign
"A soul is not exclusive to biology."

From ahughes@cmu.edu Thu Oct 24 09:59:04 1996
Path: ashpoly!cascade!transat!eunet-fr!teletel!cmu!ahughes
From: ahughes@cmu.edu (Amy Hughes)
Newsgroups: comp.sys.m68k
Subject: Re: WTB/WTT: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1996Oct24.095904.6266@cmu.edu>
Date: Thu, 24 Oct 1996 09:59:04 GMT
References: <1996Oct22.123004.9240@illinois.edu>
Organization: Carnegie Mellon University School of CS
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In article <1996Oct22.123004.9240@illinois.edu>, jpetrov@illinois.edu (Joachim Petrov) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.
> The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.

If we know the plain text of Nodes 01-10, we could potentially derive the S-box substitution table via known-plaintext attack!

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-- 
Amy Hughes
Tape trading list upon request. SASE required for international mail.