The "thread thread," about plastic/metallic threads placed in currency to track our purchases and control our movements, has some up again. (I'm reminded to put something in the Cyphernomicon FAQ about it!) * The threads are an anti-counterfeiting measure, so far as is known. (I saw a "Nova" episode of counterfeiting, and this was the reason give. Consistent with the physics, too.) * A tiny thread cannot be readily detected by "airport scanners," nor by even longer-distance scanners, unless the gain on the detector is turned up so high that many other things trigger the detector. If the threads are mostly plastic, with discontiguous metallic writing on them, then the detection problem is even harder. (Caveat: I admit the slim possibility that detectors could be tuned to resonate with the precise _length_ of such threads. Maybe. Easily thwarted by snipping, scratching, folding, and of course, RF shielding.) Dana Albrecht wrote (quoting from alt.2600)

...

Imbedded in 1991 series $20 bills (and I assume all later and higher bills) are thin plastic(?) strips with metallic writing on them. If you're careful you can remove them with a razorblade by slitting the bill's top edge and gently pulling it out. I've heard that airports will soon have "Money Detectors" that will count total cash carried per person. I'd like to figure out how the system works. I also think it would be cool for people to collect all the strips in any money they ever came in contact with and keep those in their wallets. Soon it would look like everyone was walking around with $100K's of cash, rendering their system useless.

Yeah, right. Everybody does this and the _total number of threads_ increases. Nope. Think about it.

Assuming this is true, it would seem that even good, old fashioned, paper currency doesn't provide the level of anonymity that one would think. Scary...

Dana W. Albrecht

Don't believe everything you read. Imagine what the simplest measures, like folding your currency and placing it in anything metallic would do. (For the paranoid, money clips are usually metal. Some are even full enclosures. Are these to be banned? I don't want to sound insulting here. Some conspiracy theories are interesting, plausible, and worthy of concern. All I'm suggesting is that people do some "due diligence" in estimating the likelihood of something being true. For example, another chestnut is the one about how cable t.v. boxes will be able to use the LED displays as a _camera_ to send pictures back to Big Brother. Simple physics, as well as the bandwidths and configurations involved, shows how implausible this is....and yet this urban legend shows up every few months--even here. Did you know that flashing your headlights during the day will cause gang members to respond by killing you? I know someone who says they saw it happen. Police agencies around the country are warning people not to flash their headlights during the day. --Tim May -- .......................................................................... Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay@netcom.com | anonymous networks, digital pseudonyms, zero 408-688-5409 | knowledge, reputations, information markets, W.A.S.T.E.: Aptos, CA | black markets, collapse of governments. Higher Power: 2^859433 | Public Key: PGP and MailSafe available. Cypherpunks list: majordomo@toad.com with body message of only: subscribe cypherpunks. FAQ available at ftp.netcom.com in pub/tcmay