From fsokolov@mit.edu Sun Mar 12 02:40:38 1995
Path: ashpoly!cascade!bigsur!mit!fsokolov
From: fsokolov@mit.edu (Fiona Sokolov)
Newsgroups: comp.sys.m68k
Subject: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar12.024038.3986@mit.edu>
Date: Sun, 12 Mar 1995 02:40:38 GMT
Organization: Massachusetts Institute of Technology
NNTP-Posting-Host: mit.edu
X-Newsreader: WinVN 0.99.5
Lines: 11

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.
This indicates socket U14 held a cryptographic S-box lookup table for decrypting the Stardust keystream.

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

-- 
Fiona Sokolov <fsokolov@mit.edu>
"In theory there is no difference between theory and practice."
Amiga 1200 (Blizzard 030/50) / NEXTSTEP 3.3

From bpopov@purdue.edu Sun Mar 12 05:23:38 1995
Path: ashpoly!cascade!bigsur!purdue!bpopov
From: bpopov@purdue.edu (Bruno Popov)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Mar12.052338.4196@purdue.edu>
Date: Sun, 12 Mar 1995 05:23:38 GMT
References: <1995Mar12.024038.3986@mit.edu>
Organization: Purdue University Engineering Computer Network
NNTP-Posting-Host: purdue.edu
X-Newsreader: NewsWatcher 2.0b24
Lines: 8

In article <1995Mar12.024038.3986@mit.edu>, fsokolov@mit.edu (Fiona Sokolov) 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!

-- 
Bruno Popov
Tape trading list upon request. SASE required for international mail.