From bwatanabe@purdue.edu Wed Jan 18 11:07:58 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!purdue!bwatanabe
From: bwatanabe@purdue.edu (Bruno Watanabe)
Newsgroups: comp.sys.m68k
Subject: Question: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan18.110758.3644@purdue.edu>
Date: Wed, 18 Jan 1995 11:07:58 GMT
Organization: Purdue University Engineering Computer 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.
The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.

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

-- 
=== Bruno Watanabe ===
Dept of Electrical Engineering, Purdue University Engineering Computer Network
"Row 14. No joke."

From mfischer@uu.net Wed Jan 18 20:17:58 1995
Path: ashpoly!cascade!brgate!saturno!uu!mfischer
From: mfischer@uu.net (Morag Fischer)
Newsgroups: comp.sys.m68k
Subject: Re: Question: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan18.201758.8463@uu.net>
Date: Wed, 18 Jan 1995 20:17:58 GMT
References: <1995Jan18.110758.3644@purdue.edu>
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In article <1995Jan18.110758.3644@purdue.edu>, bwatanabe@purdue.edu (Bruno Watanabe) 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!

Unsubscribe me from this list! (Wait, this is Usenet, never mind).

-- 
Morag Fischer
Tape trading list upon request. SASE required for international mail.

From sramirez@mit.edu Wed Jan 18 23:35:58 1995
Path: ashpoly!cascade!transat!ukc!fennimore!mit!sramirez
From: sramirez@mit.edu (Sun-mi Ramírez)
Newsgroups: comp.sys.m68k
Subject: Re: Question: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan18.233558.2158@mit.edu>
Date: Wed, 18 Jan 1995 23:35:58 GMT
References: <1995Jan18.110758.3644@purdue.edu> <1995Jan18.201758.8463@uu.net>
Organization: Massachusetts Institute of Technology
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In article <1995Jan18.201758.8463@uu.net>, mfischer@uu.net (Morag Fischer) writes:
> If we know the plain text of Nodes 01-10, we could potentially derive the S-box substitution table via known-plaintext attack!

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

-- 
Sun-mi Ramírez
Opinions expressed are solely my own and not those of Massachusetts Institute of Technology.
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