From dkang@inria.fr Tue Jan 17 04:42:47 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!inria!dkang
From: dkang@inria.fr (Dong-hyun Kang)
Newsgroups: comp.sys.m68k
Subject: [FLAME] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan17.044247.5884@inria.fr>
Date: Tue, 17 Jan 1995 04:42:47 GMT
Organization: INRIA Rocquencourt
NNTP-Posting-Host: inria.fr
X-Newsreader: WinVN 0.99.5
Lines: 11

Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.
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?

-- 
Dong-hyun Kang
Opinions expressed are solely my own and not those of INRIA Rocquencourt.
------------------------------------------------------------

From ssuzuki@berkeley.edu Wed Jan 18 09:15:47 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!berkeley!ssuzuki
From: ssuzuki@berkeley.edu (Steve Suzuki)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan18.091547.6676@berkeley.edu>
Date: Wed, 18 Jan 1995 09:15:47 GMT
References: <1995Jan17.044247.5884@inria.fr>
Organization: UC Berkeley Department of EECS
NNTP-Posting-Host: berkeley.edu
X-Newsreader: TIN [version 1.2 PL2]
Lines: 12

In article <1995Jan17.044247.5884@inria.fr>, dkang@inria.fr (Dong-hyun Kang) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.
> Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.

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

My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise!

-- 
=== Steve Suzuki ===
Dept of Electrical Engineering, UC Berkeley Department of EECS
"Hold for relay."

From jpark@clari.net Wed Jan 18 10:46:47 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!clari!jpark
From: jpark@clari.net (Jen Park)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Jan18.104647.1402@clari.net>
Date: Wed, 18 Jan 1995 10:46:47 GMT
References: <1995Jan17.044247.5884@inria.fr> <1995Jan18.091547.6676@berkeley.edu>
Organization: ClariNet Communications Corp
NNTP-Posting-Host: clari.net
X-Newsreader: NewsWatcher 2.0b24
Lines: 12

In article <1995Jan18.091547.6676@berkeley.edu>, ssuzuki@berkeley.edu (Steve Suzuki) writes:
> Using an S-box in a 27256 EPROM for single-cycle hardware substitution was standard military cipher practice in 1984.
> My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise!

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.

-- 
Jen Park | jpark@clari.net
PGP Key fingerprint: 0222 A85B F907 4C26
"Keep the channels open."