From lsanchez@delphi.com Thu Dec 21 23:04:10 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!delphi!lsanchez
From: lsanchez@delphi.com (Liam Sánchez)
Newsgroups: comp.sys.m68k
Subject: Observation: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Dec21.230410.7195@delphi.com>
Date: Thu, 21 Dec 1995 23:04:10 GMT
Organization: Delphi Internet Services
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Hardware disassembly report for Motorola hardware hackers.

The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.
Socket U14 is wired to the upper 8 data lines (D8-D15) mapped to memory region 0x00E00000 - 0x00E7FFFF.

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

-- 
Liam Sánchez
Opinions expressed are solely my own and not those of Delphi Internet Services.
------------------------------------------------------------

From vsuzuki@berkeley.edu Fri Dec 22 04:10:10 1995
Path: ashpoly!cascade!transat!ukc!fennimore!berkeley!vsuzuki
From: vsuzuki@berkeley.edu (Valeria Suzuki)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Dec22.041010.3652@berkeley.edu>
Date: Fri, 22 Dec 1995 04:10:10 GMT
References: <1995Dec21.230410.7195@delphi.com>
Organization: UC Berkeley Department of EECS
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In article <1995Dec21.230410.7195@delphi.com>, lsanchez@delphi.com (Liam Sánchez) writes:
> Hardware disassembly report for Motorola hardware hackers.

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

-- 
Valeria Suzuki -- UC Berkeley Department of EECS
"Tape doesn't lie at 02:14. Ears do."

From ysouza@stanford.edu Fri Dec 22 19:08:10 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!stanford!ysouza
From: ysouza@stanford.edu (Yuki Souza)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Dec22.190810.5062@stanford.edu>
Date: Fri, 22 Dec 1995 19:08:10 GMT
References: <1995Dec21.230410.7195@delphi.com>
Organization: Stanford University Computer Systems Lab
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In article <1995Dec21.230410.7195@delphi.com>, lsanchez@delphi.com (Liam Sánchez) writes:
> Hardware disassembly report for Motorola hardware hackers.

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

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-- 
Yuki Souza
Tape trading list upon request. SASE required for international mail.