On Sat, 14 Apr 2012 19:35:45 -0700, Steve B wrote:

"Ignoramus31455" wrote

What are you trying to accomplish, prove ownership, or have an
automatic inventory system?

i

Identify ownership. During the 70's Hughes Tool Company (Howard Hughes
oil drill bits) could not be purchased. They were leased. There was NO
doubt EVER about ownership. Hughes owned it, and they never sold it,
only leased it. A bit had to be accompanied with proper lease papers,
or it was considered stolen property, and recoverable by any Hughes
agent, LEO, or just a savvy oilfield worker who could take it to Hughes
and get a bounty. NOBODY EVER owned one. There was no question.

I am investigating this for my equipment. Of course, I would have to
have an enforcer and collector, but I think it would be worth it. I
just don't really think in my heart of hearts that a chip idea would
work.

Again, what are you trying to accomplish? I wouldn't depend on the chip
as your last line of defense against thieves or forgers. You can use
them as a first -- and convenient -- line of defense, but ultimately I
think you'll want to have a secret serial number embedded in the thing in
at least one, if not several places.

I'd consider things like:

* serial numbers stamped on mating surfaces or inside of cases,
that require disassembly to see.
* serial numbers that are otherwise incorporated into machined
surfaces in such a way that obliterating the serial number
means having to rebuild the machine.
* serial numbers encoded in tungsten or lead, behind a
welded-in boss, so they'll show up in an inspection x-ray
* Cast your company name and the model number into the parts,
and _never ever_ sell anything -- so that if it ever comes
to a court case you can document that nothing has been
released into the wild.

And remember that no matter how good a lock you put on your door, if the
stuff inside the building is attractive enough the thieves will just cut
through the wall or tunnel through the floor -- the only anti-theft
device that works perfectly is to destroy what you value in a big hot
fire, and that doesn't help you much.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com