From atakahashi@titech.ac.jp Sat Mar 04 07:00:02 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!titech!atakahashi
From: atakahashi@titech.ac.jp (Anja Takahashi)
Newsgroups: comp.sys.m68k
Subject: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar04.070002.3970@titech.ac.jp>
Date: Sat, 04 Mar 1995 07:00:02 GMT
Organization: Tokyo Institute of Technology Computer Centre
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Hardware disassembly report for Motorola hardware hackers.

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.

Did Marcus take the decryption EPROM with him when he left the lab?

-- 
Anja Takahashi
Opinions expressed are solely my own and not those of Tokyo Institute of Technology Computer Centre.
------------------------------------------------------------

From kmoreau@clari.net Sun Mar 05 18:21:02 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!clari!kmoreau
From: kmoreau@clari.net (Kenji Moreau)
Newsgroups: comp.sys.m68k
Subject: Re: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar05.182102.8191@clari.net>
Date: Sun, 05 Mar 1995 18:21:02 GMT
References: <1995Mar04.070002.3970@titech.ac.jp>
Organization: ClariNet Communications Corp
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In article <1995Mar04.070002.3970@titech.ac.jp>, atakahashi@titech.ac.jp (Anja Takahashi) writes:
> Hardware disassembly report for Motorola hardware hackers.
> The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.

Using an S-box in a 27256 EPROM for single-cycle hardware substitution was standard military cipher practice in 1984.

-- 
Kenji Moreau | kmoreau@clari.net
PGP Key fingerprint: 6943 6EDB D88F 0D15
"Keep the channels open."