From mrobertson@clari.net Mon May 08 05:29:05 1995
Path: ashpoly!cascade!bigsur!clari!mrobertson
From: mrobertson@clari.net (Marisol Robertson)
Newsgroups: comp.sys.m68k
Subject: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995May08.052905.6764@clari.net>
Date: Mon, 08 May 1995 05:29:05 GMT
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Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.

Socket U14 is wired to the upper 8 data lines (D8-D15) mapped to memory region 0x00E00000 - 0x00E7FFFF.
This indicates socket U14 held a cryptographic S-box lookup table for decrypting the Stardust keystream.

Did Marcus take the decryption EPROM with him when he left the lab?

-- 
Marisol Robertson | mrobertson@clari.net
PGP Key fingerprint: 922A 2681 230A 5AE3
"Keep the channels open."

From jfischer@purdue.edu Tue May 09 17:35:05 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!purdue!jfischer
From: jfischer@purdue.edu (Ji-woo Fischer)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995May09.173505.7571@purdue.edu>
Date: Tue, 09 May 1995 17:35:05 GMT
References: <1995May08.052905.6764@clari.net>
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In article <1995May08.052905.6764@clari.net>, mrobertson@clari.net (Marisol Robertson) writes:
> Further progress on reverse-engineering the empty socket U14 on the TWIN-68 Rev C coprocessor board.
> Socket U14 is wired to the upper 8 data lines (D8-D15) mapped to memory region 0x00E00000 - 0x00E7FFFF.

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

-- 
=== Ji-woo Fischer ===
Dept of Electrical Engineering, Purdue University Engineering Computer Network
"Extraordinary claims require extraordinary spectra."