From cmoreno@utexas.edu Thu Apr 06 03:40:11 1995
Path: ashpoly!cascade!bigsur!utexas!cmoreno
From: cmoreno@utexas.edu (Camila Moreno)
Newsgroups: comp.sys.m68k
Subject: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Apr06.034011.4443@utexas.edu>
Date: Thu, 06 Apr 1995 03:40:11 GMT
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Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

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.

-- 
Camila Moreno <cmoreno@utexas.edu>
*PLONK* filter active for trolls.
Atari Falcon 030 - NetBSD 1.0

From glindqvist@tum.de Thu Apr 06 15:09:11 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!tum!glindqvist
From: glindqvist@tum.de (Göran Lindqvist)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Apr06.150911.8438@tum.de>
Date: Thu, 06 Apr 1995 15:09:11 GMT
References: <1995Apr06.034011.4443@utexas.edu>
Organization: Technische Universität München
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In article <1995Apr06.034011.4443@utexas.edu>, cmoreno@utexas.edu (Camila Moreno) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

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

-- 
Göran Lindqvist | glindqvist@tum.de
PGP Key fingerprint: 3F03 E9E8 A3A0 8E09
"Keep the channels open."

From rito@kth.se Fri Apr 07 07:46:11 1995
Path: ashpoly!cascade!bigsur!kth!rito
From: rito@kth.se (Raj Ito)
Newsgroups: comp.sys.m68k
Subject: Re: [SPECULATION] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Apr07.074611.3831@kth.se>
Date: Fri, 07 Apr 1995 07:46:11 GMT
References: <1995Apr06.034011.4443@utexas.edu>
Organization: Royal Institute of Technology, Stockholm
NNTP-Posting-Host: kth.se
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In article <1995Apr06.034011.4443@utexas.edu>, cmoreno@utexas.edu (Camila Moreno) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.
> 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.

-- 
Raj Ito -- Royal Institute of Technology, Stockholm
"Hold for relay."