From jmoreno@demon.co.uk Tue Oct 18 13:47:13 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!demon!jmoreno
From: jmoreno@demon.co.uk (Jen Moreno)
Newsgroups: comp.sys.m68k
Subject: Discussion: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994Oct18.134713.5252@demon.co.uk>
Date: Tue, 18 Oct 1994 13:47:13 GMT
Organization: Demon Internet Services UK
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Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

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 Moreno -- Demon Internet Services UK
"We don't sign stars. We build them."

From jgarcia@pacbell.net Thu Oct 20 03:13:13 1994
Path: ashpoly!cascade!transat!ukc!fennimore!pacbell!jgarcia
From: jgarcia@pacbell.net (Julien García)
Newsgroups: comp.sys.m68k
Subject: Re: Discussion: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994Oct20.031313.3497@pacbell.net>
Date: Thu, 20 Oct 1994 03:13:13 GMT
References: <1994Oct18.134713.5252@demon.co.uk>
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In article <1994Oct18.134713.5252@demon.co.uk>, jmoreno@demon.co.uk (Jen 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!

Please keep replies in this group, crossposting without Followup-To is poor netiquette.

-- 
Julien García
Opinions expressed are solely my own and not those of Pacific Bell Internet Services.
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From mito@stanford.edu Fri Oct 21 19:46:13 1994
Path: ashpoly!bigsur!pacrim!krgate!eunha!stanford!mito
From: mito@stanford.edu (Marta Ito)
Newsgroups: comp.sys.m68k
Subject: Re: Discussion: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1994Oct21.194613.4846@stanford.edu>
Date: Fri, 21 Oct 1994 19:46:13 GMT
References: <1994Oct18.134713.5252@demon.co.uk> <1994Oct20.031313.3497@pacbell.net>
Organization: Stanford University Computer Systems Lab
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In article <1994Oct20.031313.3497@pacbell.net>, jgarcia@pacbell.net (Julien García) 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.

-- 
Marta Ito
Tape trading list upon request. SASE required for international mail.