From jjohansson@delphi.com Mon Mar 13 22:45:25 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!delphi!jjohansson
From: jjohansson@delphi.com (Jen Johansson)
Newsgroups: comp.sys.m68k
Subject: [FLAME] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar13.224525.1733@delphi.com>
Date: Mon, 13 Mar 1995 22:45:25 GMT
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Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.
Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.

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

-- 
Jen Johansson -- Delphi Internet Services
"A soul is not exclusive to biology."

From asato@cern.ch Tue Mar 14 18:12:25 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!cern!asato
From: asato@cern.ch (Andrei Sato)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar14.181225.1276@cern.ch>
Date: Tue, 14 Mar 1995 18:12:25 GMT
References: <1995Mar13.224525.1733@delphi.com>
Organization: European Laboratory for Particle Physics, Geneva
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In article <1995Mar13.224525.1733@delphi.com>, jjohansson@delphi.com (Jen Johansson) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.
> The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.

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

-- 
Andrei Sato
Tape trading list upon request. SASE required for international mail.

From bpark@cam.ac.uk Wed Mar 15 23:46:25 1995
Path: ashpoly!cascade!mxgate!coyoacan!cam!bpark
From: bpark@cam.ac.uk (Brian Park)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar15.234625.2878@cam.ac.uk>
Date: Wed, 15 Mar 1995 23:46:25 GMT
References: <1995Mar13.224525.1733@delphi.com>
Organization: University of Cambridge Computer Laboratory
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In article <1995Mar13.224525.1733@delphi.com>, jjohansson@delphi.com (Jen Johansson) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

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

-- 
Brian Park
Opinions expressed are solely my own and not those of University of Cambridge Computer Laboratory.
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