From: wcs@anchor.ho.att.com
Date: Mon, 26 Apr 93 21:35:30 PDT
To: smb@ulysses.att.com
Subject: Mykotronx and VLSI data sheets
Message-ID: <9304270435.AA09033@anchor.ho.att.com>
MIME-Version: 1.0
Content-Type: text


The data sheets arrived today!   
(Steve - I gave Matt a copy; I can fax it to you if yours hasn't shown) 
(Cypherpunks - Mykotronx 310-533-8100 fax-0527, VLSI 408-434-3100 fax-263-2511)
The VLSI material didn't have anything Clipper-specific -
lots of stuff on their ASIC libraries and chips, and some information on 
their tamper-proof technology.  Their DES chip does 192 Mb/s, and they've
got a vocoder chip for 13 kb/s GSM as well as 32 kb/s ADPCM G.721,
ARM RISC, Z80 cores, high-speed comms stuff, PC support ASICs, etc.

The Mykotronx material was interesting.  It was about 18 pages long,
and there are functional diagrams, pinouts, timing diags, command sets.
It looks like there may be two versions, one commercial, one industrial-hard.
The chip is 28-pin PLCC, with 4 bits control input, 8 leads for input/
output/config/status/test/alarm depending on command, the usual power,
clock, strobe, busy, reset, and alarm leads, and two leads for
higher-voltage write-once PROM.  The internal clock is 15 MHz, and I'm
not sure how fast it goes if you clock it externally (it uses the internal
clock when it's doing the fun stuff, but can use externals for I/O, etc.)
It looks like the encryption phase takes 64 clock cycles, but I'm not an 
electrician so I can't guarantee that that's what the timing diags mean;
if that's the case it would seem to be slower than 16 mb/s throughput
given I/O time?

There are 5 functional blocks: controller, algorithm, Data Bus Buffer,
self-test, and clock.  There's an internal data bus (how wide? 8 bits?)
with the controller, data buffer, and external clock accessible from outside,
the self-test generating two output leads only, and the algorithm block
isolated (only connected to the bus and self-test.)

The basic sequence of operations, once the chip has booted and tested,
is that you feed commands to initialize cryptographic variables (key, IV),
tell it to encrypt or decrypt, strobe in data, let it crunch, and strobe
out results.  It's picky about getting commands in the right order, 
and rejects anything it isn't willing to do for security reasons.  

It can operate in 7 different modes: ECB-64, CBC-64, OFB-64, CFB-64/32/16/8.
The number of bytes read or written depends on the mode, but I was interested
to find that I couldn't tell from the data sheets how many bytes that is,
which either means they deliberately aren't telling us where the wiretap 
block is or else they assume that the Output Buffer Full and Input Buf Empty
leads are all you care about; I'll try to find a tasteful way to ask them.

Commands:
- Reset
- Write Random Seed - must be done at startup; there's a pseudo-random 
	generator for IVs.  If you give it a zero, it asks for a better seed.
- Write Config Register - done second, picks operating mode.
	If you're in IDLE mode, you need to do this before 
	writing the CV or IV.
- Write Crypto-Variable (CV) (loads 10 bytes key, 3 bytes checksum,
	automagically checks key when loaded.)
- Write Initialization Vector (IV) - you can load it or generate.
- Generate IV - using the pseudo-random.  Outputs to data bus when done.
- Start Encrypt Block - read data off bus, crunch, wait for Read Output, IDLE
- Read Output - strobes out output
- Start Decrypt Block - read data, crunch, wait for Read Output, repeat
	until you get a Terminate or other command
- Terminate Encrypt/Decrypt - stop doing encryption (IDLE?)
- Save Current State - output 8 bytes of state to data bus
- Restore Current State - input 8 bytes of state from data bus
- Read Status Register - outputs to bus
- Read Test/Alarm Register - outputs to bus
- Write Test/Alarm Register - read from bus, do tests

If you want to order a copy, they were pretty quick about delivering it.
The person I talked to was John Droge, VP, Program Development.
Approximate prices are $30 (qty. 10,000), no mention of engineering samples,
quotations on a case-by-case basis for now.


			Bill Stewart
			
# Bill Stewart    wcs@anchor.ho.att.com  +1-908-949-0705 Fax-4876
# AT&T Bell Labs, Room 4M-312, Crawfords Corner Rd, Holmdel, NJ  07733-3030