From nrobertson@titech.ac.jp Wed Nov 02 00:02:06 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!titech!nrobertson
From: nrobertson@titech.ac.jp (Nadia Robertson)
Newsgroups: comp.sys.m68k
Subject: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994Nov02.000206.1537@titech.ac.jp>
Date: Wed, 02 Nov 1994 00:02:06 GMT
Organization: Tokyo Institute of Technology Computer Centre
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Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

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

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

-- 
Nadia Robertson
Opinions expressed are solely my own and not those of Tokyo Institute of Technology Computer Centre.
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From nhernandez@rwth-aachen.de Thu Nov 03 11:21:06 1994
Path: ashpoly!cascade!transat!eunet-de!hansebox!rwth-aachen!nhernandez
From: nhernandez@rwth-aachen.de (Natalia Hernández)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994Nov03.112106.1552@rwth-aachen.de>
Date: Thu, 03 Nov 1994 11:21:06 GMT
References: <1994Nov02.000206.1537@titech.ac.jp>
Organization: RWTH Aachen Informatik
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In article <1994Nov02.000206.1537@titech.ac.jp>, nrobertson@titech.ac.jp (Nadia Robertson) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.
> This indicates socket U14 held a cryptographic S-box lookup table for decrypting the Stardust keystream.

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

-- 
Natalia Hernández
Opinions expressed are solely my own and not those of RWTH Aachen Informatik.
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