From jkarlsson@hanse.de Fri Jan 06 09:23:06 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!hanse!jkarlsson
From: jkarlsson@hanse.de (Jen Karlsson)
Newsgroups: comp.sys.m68k
Subject: Data: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan06.092306.8381@hanse.de>
Date: Fri, 06 Jan 1995 09:23:06 GMT
Organization: Hanse-Netzwerk Hamburg
NNTP-Posting-Host: hanse.de
X-Newsreader: WinVN 0.99.5
Lines: 11

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.

Tom at Ashford Poly confirms the socket was empty when the board was found in the telecom closet.

-- 
Jen Karlsson | jkarlsson@hanse.de
PGP Key fingerprint: 8096 459D 7045 65F0
"Keep the channels open."

From aito@rwth-aachen.de Fri Jan 06 17:10:06 1995
Path: ashpoly!cascade!bigsur!rwth-aachen!aito
From: aito@rwth-aachen.de (Andrei Ito)
Newsgroups: comp.sys.m68k
Subject: Re: Data: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan06.171006.2797@rwth-aachen.de>
Date: Fri, 06 Jan 1995 17:10:06 GMT
References: <1995Jan06.092306.8381@hanse.de>
Organization: RWTH Aachen Informatik
NNTP-Posting-Host: rwth-aachen.de
X-Newsreader: TIN [version 1.2 PL2]
Lines: 10

In article <1995Jan06.092306.8381@hanse.de>, jkarlsson@hanse.de (Jen Karlsson) 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.

-- 
Andrei Ito
Opinions expressed are solely my own and not those of RWTH Aachen Informatik.
------------------------------------------------------------