Re: [NOISE] Cable-TV-Piracy-Punks

At 7:36 PM 3/31/96, Mike Duvos wrote:

>We aren't talking about IC masks here.  We are talking about
>electrostatic charges which would instantly leak away if the
>insulation around them were in the least bit compromised.

The surface layers above the active portion of a chip can be stripped away
and chip remains functional. This includes the outer packaging layers
(epoxy, or of course, ceramic with metal lids) and parts of the so-called
"scratch protection," usually a type of silicate glass.

The active capacitors are not affected by removal of these layers.

>Such data wouldn't even survive the preparation for scanning
>microscopy, much less the actual inspection process.

Actually, we did it all the time in my lab at Intel, and I understand from
my former co-workers that the technology has only gotten better. (This does
not mean voltage contrast is easy. For one thing, modern chips have 3-5
metal layers, due to spectacular advances in chem-mechanical polishing, and
each metal layer acts as a ground plane shielding the lower layers from
visibility and inspection with electron beams. And EPROM and EEPROM cells
are effectively impossible to analyze, for various reasons.)

This does not mean I think reverse-engineering of smart cards or satellite
boxes is easy.

SQUIDs won't do it, either.

--Tim May

Boycott "Big Brother Inside" software!
We got computers, we're tapping phone lines, we know that that ain't allowed.
---------:---------:---------:---------:---------:---------:---------:----
Timothy C. May              | Crypto Anarchy: encryption, digital money,
tcmay@got.net  408-728-0152 | anonymous networks, digital pseudonyms, zero
W.A.S.T.E.: Corralitos, CA  | knowledge, reputations, information markets,
Higher Power: 2^756839 - 1  | black markets, collapse of governments.
"National borders aren't even speed bumps on the information superhighway."

tcmay@got.net (Timothy C. May) writes:

 > The surface layers above the active portion of a chip can
 > be stripped away and chip remains functional. This includes
 > the outer packaging layers (epoxy, or of course, ceramic
 > with metal lids) and parts of the so-called "scratch
 > protection," usually a type of silicate glass.

 > The active capacitors are not affected by removal of these
 > layers.

True, but removing packaging materials and protective layers is a
long way from imaging the charges tunneled to and from the
floating gates of EEPROM cells, which is the particular
application we are discussing.

Also bear in mind that in a real device, the tamper-resistant
packaging will be considerably more intractable than conventional
semiconductor packaging, and these devices are often designed to
automatically erase all data if signs of tampering are detected.

 > Actually, we did it all the time in my lab at Intel, and I
 > understand from my former co-workers that the technology has
 > only gotten better. (This does not mean voltage contrast is
 > easy. For one thing, modern chips have 3-5 metal layers, due
 > to spectacular advances in chem-mechanical polishing, and
 > each metal layer acts as a ground plane shielding the lower
 > layers from visibility and inspection with electron beams.

Yes.  This is truely impressive technology which continues to
improve with leaps and bounds.  SEM/TEM/STEM voltage-contrast
techniques are a major tool for failure analysis of semiconductor
devices, and AFM instruments can do voltage measurements on
running devices down to nanometer and picosecond resolutions.

 > And EPROM and EEPROM cells are effectively impossible to
 > analyze, for various reasons.)

Correct.  Which is one of the reasons why they are currently the
favored mode of storage for smart card applications.

 > This does not mean I think reverse-engineering of smart
 > cards or satellite boxes is easy.

While I don't necessarily disagree with Perry that sufficiently
advanced technology can reverse-engineer almost anything (the
kind of advanced technology that is indistinguishable from
magick), I think there are practical engineering difficulties in
doing such things today which are either insurmountable or at the
very least a strong indication that there are better ways to
approach the problem.

 > SQUIDs won't do it, either.

At the risk of offending Mr. Squid, I must say that SQUIDs were a
big disappointment given the initial hype and expended research
funds.

BTW, I attempted to read all your writings on "Tamper-Resistant
Modules" in the list archives, but as fate would have it, hks.net
has taken the archives offline for a few days to do some sort of
upgrade.

I did get this very nice Cyber Wallet thing off their Web Page,
however, which uses "DES and Full 768 Bit RSA." Although I must
admit I'm not exactly sure what "full" means in this particular
context. :)

--
     Mike Duvos         $    PGP 2.6 Public Key available     $
     mpd@netcom.com     $    via Finger.                      $