From tgonzalez@earthlink.net Thu May 26 19:11:38 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!tgonzalez
From: tgonzalez@earthlink.net (Tobias González)
Newsgroups: comp.sys.m68k
Subject: WTB/WTT: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994May26.191138.6744@earthlink.net>
Date: Thu, 26 May 1994 19:11:38 GMT
Organization: EarthLink Network
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Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.
This indicates socket U14 held a cryptographic S-box lookup table for decrypting the Stardust keystream.

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

-- 
Tobias González
Opinions expressed are solely my own and not those of EarthLink Network.
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From scampbell@purdue.edu Sat May 28 10:56:38 1994
Path: ashpoly!cascade!brgate!saturno!purdue!scampbell
From: scampbell@purdue.edu (Sun-mi Campbell)
Newsgroups: comp.sys.m68k
Subject: Re: WTB/WTT: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994May28.105638.5488@purdue.edu>
Date: Sat, 28 May 1994 10:56:38 GMT
References: <1994May26.191138.6744@earthlink.net>
Organization: Purdue University Engineering Computer Network
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In article <1994May26.191138.6744@earthlink.net>, tgonzalez@earthlink.net (Tobias González) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

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

-- 
=== Sun-mi Campbell ===
Dept of Electrical Engineering, Purdue University Engineering Computer Network
"Marcus is not one man."

From lstewart@cern.ch Sat May 28 12:43:38 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cern!lstewart
From: lstewart@cern.ch (Lisa Stewart)
Newsgroups: comp.sys.m68k
Subject: Re: WTB/WTT: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994May28.124338.5678@cern.ch>
Date: Sat, 28 May 1994 12:43:38 GMT
References: <1994May26.191138.6744@earthlink.net>
Organization: European Laboratory for Particle Physics, Geneva
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In article <1994May26.191138.6744@earthlink.net>, tgonzalez@earthlink.net (Tobias González) 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!

-- 
Lisa Stewart
Opinions expressed are solely my own and not those of European Laboratory for Particle Physics, Geneva.
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