From eivanov@pacbell.net Thu Jul 13 13:42:21 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pacbell!eivanov
From: eivanov@pacbell.net (Elaine Ivanov)
Newsgroups: comp.sys.m68k
Subject: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jul13.134221.5147@pacbell.net>
Date: Thu, 13 Jul 1995 13:42:21 GMT
Organization: Pacific Bell Internet Services
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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.
Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.

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

-- 
=== Elaine Ivanov ===
Dept of Electrical Engineering, Pacific Bell Internet Services
"Row 14. No joke."

From mweber@rwth-aachen.de Fri Jul 14 14:19:21 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!rwth-aachen!mweber
From: mweber@rwth-aachen.de (Min-jun Weber)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jul14.141921.9980@rwth-aachen.de>
Date: Fri, 14 Jul 1995 14:19:21 GMT
References: <1995Jul13.134221.5147@pacbell.net>
Organization: RWTH Aachen Informatik
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In article <1995Jul13.134221.5147@pacbell.net>, eivanov@pacbell.net (Elaine Ivanov) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

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

-- 
Min-jun Weber -- RWTH Aachen Informatik
"We don't sign stars. We build them."

From eschneider@titech.ac.jp Sun Jul 16 05:52:21 1995
Path: ashpoly!cascade!mxgate!coyoacan!titech!eschneider
From: eschneider@titech.ac.jp (Élodie Schneider)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jul16.055221.1880@titech.ac.jp>
Date: Sun, 16 Jul 1995 05:52:21 GMT
References: <1995Jul13.134221.5147@pacbell.net>
Organization: Tokyo Institute of Technology Computer Centre
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In article <1995Jul13.134221.5147@pacbell.net>, eivanov@pacbell.net (Elaine Ivanov) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

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

Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns.

-- 
Élodie Schneider -- Tokyo Institute of Technology Computer Centre
"In theory there is no difference between theory and practice."