From dperez@mit.edu Fri Oct 13 23:44:09 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!mit!dperez
From: dperez@mit.edu (Dave Pérez)
Newsgroups: comp.sys.m68k
Subject: Data: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Oct13.234409.3743@mit.edu>
Date: Fri, 13 Oct 1995 23:44:09 GMT
Organization: Massachusetts Institute of Technology
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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.

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

-- 
Dave Pérez <dperez@mit.edu>
SupraFAXModem 28.8 @ ISDN 64k bps
"Tape doesn't lie at 02:14. Ears do."

From creyes@kiae.su Mon Oct 16 03:44:09 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!kiae!creyes
From: creyes@kiae.su (Camila Reyes)
Newsgroups: comp.sys.m68k
Subject: Re: Data: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Oct16.034409.2119@kiae.su>
Date: Mon, 16 Oct 1995 03:44:09 GMT
References: <1995Oct13.234409.3743@mit.edu>
Organization: Kurchatov Institute of Atomic Energy, Moscow
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In article <1995Oct13.234409.3743@mit.edu>, dperez@mit.edu (Dave Pérez) writes:
> 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.

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

-- 
Camila Reyes | creyes@kiae.su
PGP Key fingerprint: 5821 81AE 2468 DA5E
"Keep the channels open."