[IP] One Internet provider's view of FBI's CALEA wiretap push

[Thomas Shaddack]

On Fri, 23 Apr 2004, Major Variola (ret) wrote:

> >> filesystems (etc) with layers of deniable stego.
> >Are there any decent implementations for Linux/BSD/NT?
>
> I haven't looked recently.  One property that such a FS or app should
> have is that it is useful for something *else* besides stego & duress
> layers. Maybe a watermark :-) management tool that can embed multiple
> watermarks that don't interfere.  Hmm... a meaty problem... tasty, with
> heavy theory sauce..

Regarding filesystems, some time ago I came up with an idea of a
filesystem as a block device that has the filesystem handling code in its
bootblock area in a bytecode. Mount the fs, it reads the functions into
the interpreter's sandbox. Could be useful especially for read-only media
that would be using exotic encryption or compression algorithms, and
quick portability of them between various OSes; you have to develop only
the interpreter and the filesystem API for any OS in question, the rest
is on the medium itself.

I recently stumbled over an extremely interesting Linux project, "FUSE" -
filesystem in userspace. The fuse.o module serves as an interface between
the kernel and user space, relaying the filesystem-related calls. It's
quite robust approach, as any crash of the external filesystem code is in
userspace and is unlikely to take down the machine itself. Wondering if
something like that could be written for Windows. Would simplify a lot of
things.

> >There are magnesium rods on the camping market, sold as firestarters for
> >very bad weather.
>
> One can also buy mag ribbon which is more convenient than the
> mini-ingots you are referring to.  I know that pyrotechs coat Mg curls
> and the like with blackpowder paste (apply wet then dry).  A coil of
> coated ribbon and a rocket-igniter would make a neat little
> daughterboard :-)  Just don't take it on an airplane. There are patents
> on similar, of course.

Somebody mentioned here the trick with KMnO4 and glycerol. I saw this
experiment in elementary school, where it was shown as a demonstration
that mixing "ordinary" things may give extraordinary results - it was
shown to light up a glob of magnesium shavings. A setup with a dongle
circuitboard covered with an insulating/protective varnish, a magnesium
strip attached over the memory chip (held in place by steel wire thick
enough to keep it there even while burning, for long enough to deliver
enough heat into the chip, or wrapped around the chip and the board), the
strip coated with caked permanganate, and a glass vial with glycerol in
the dongle's casing, could be usable for the field use - if you get enough
time to drop the dongle and step on it. Electrical ignition of the Mg
strip may be useful in the setups when the device is connected to home
security system or machine movement sensors.

A purely electronic system would have an advantage, though - could be
shipped much easier as it won't contain more "dangerous" components than a
lithium or silver-oxide cell. Maybe a microcontroller with a SRAM chip,
with the data stored as XORs of pairs of cells, and the micro periodically
inverting the pairs, to prevent the "remembering" in the SRAM cells after
a power-off? (Related question: are there any SRAM chips with smaller
capacity, that would have smaller case and smaller number of pins?)

> Testing might get expensive unless you can get destructive-test dongles
> cheaply, and how much effort do you expend trying to read the data?

Or replace the test dongles with test rig with a mechanically similar
chip; new serial EEPROMs in SMD casings can be bought for as cheap as
USD1/3-1/4, maybe even less. We don't need to completely obliterate the
chip; we need to heat it just enough to get the electrons from the
floating gates (maybe my terminology is wrong, but if you saw a pic of an
EEPROM or FEPROM cell, you are likely to know what I mean), get them over
the not-that-high energetical barrier so they can (and will) jump back and
forth freely, discharge the memory cells. Then not even the most expensive
atomic-level machinery can recover the original content. If the
temperature is enough to recrystallize the silicon at the chip surface, it
should have a rather wide safety margin. The casings of the SMD chips are
fairly thin - under a millimeter between the surface and the chip, so even
a relatively small strip should be enough. Tests can be done even with
discarded chips, as the remains aren't required (nor supposed) to be
functional anyway - they have to be examined by eg. optical microscopy.
Electron microscopy would be the best - but that's outside of the reach of
a "garage technician"; maybe an university or an industrial lab could be
hired or bribed to do the tests, though.