Gps for misplaced laptop?

IFF mis-use in WWII was a fairly well described in a book "The Wizard War" by Reginald Jones. The allies were losing an unconcionable number of bombers to German radar and RF detection systems. These were all new to both sides and consistantly misused until the problems were obvious. The British bomber crews seemed to have the impression that the IFF units would somehow affect the anti-aircraft batteries and their search lights. So, against orders, they would turn on the IFF transponders, giving the Germans substantial warning as to the time and direction of a bomber attack. They never could resist turning it on so they were eventually removed and not used.

No. The BC-645 was really crude. Worked at 420MHz using a "doorknob" tube. The receiver would decode two pulses with controlled spacing. If the spacing was right, it would respond with an AM modulated tone burst. The later AN/APX-6 worked on about 800-1200Mhz and worked somewhat like the current civilian radar transponders (encoding altimeter). The British had similar systems with different designations:

I'm not too worried. If the military actually turned everything on all at once, nothing would work, everything would interfere with everything else, and the whole mess would probably blow a fuse. I've seen it happen. Sorry, no details.

A code plug and a key. It required 24VDC from the aircraft to initiate the charge.

Neither. The military was deploying the SCR-584 radar at the time for anti-aircraft gun control. It has the bad habit of shooting down anything that flew overhead. The idea behind IFF was to prevent friendly fire from shooting down the bombers as well as warning night fighters that they have an enemy target.

I obviously didn't try it to find out if there was a delay. I suspect it was instantaneous initiation.

Learn by Destroying(tm)?

The cylindrical locks are worthless in that environment. Less than 10 seconds to open my Kensington.

Window? In an office? On the ground floor? Wow. And a laptop within reach of the window?

I worry about a smash and grab in my car. The back windows are so heavily tinted that you can't really see the black laptop bag, but I usually cable-lock it to the seat, and try to cover it with something.

I have thought about locking the laptop to the seat on an airplane, in case I have to wander off for a while.

I like the cellphone in the bag trick. I haven't figured out what to do with my retired ATTWS phone yet. Charge it up. leave it on in the laptop bag. Set it to auto-answer (oops, it's not activated).

From being left alone on an airplane? Wouldn't you be able to narrow down the list of suspects a bit?

Interesting. Didn't even know IFF was in use during WW2. Never even thought about them having an embedded charge, but that makes perfect sense. Were the IFF codes (and encryption, if used?) hardcoded back then? I worked satcom in the military up until about short time ago (4 years) and in the "worst case scenerio" (million Chinamen coming over the hill), at the top of the emergency actions would be to destroy all of the crypto -- but today, they are channels and procedures in place should the worst (crypto compromise) ever occur and it could be resolved, even at theater levels, rather quickly. Not a subject I'd get into details over, obviously. There is enough on it (too much?) at fas.org, anyway.

How was the thermite fused for the WW2 IFF's? Was there something that detected when the aircraft impacted or did the pilot hit a switch or something? Was there a time delay between the activation and fusing, or would it just start buring right away?

Learn something new every day. :^)

Cheers, Eric

I'm not attacking the lock. That's usually the strongest part. I attack the cable, which the Dremel cuts through like butter. I'm a bit concerned about the steel core in the cable, but if it's relatively small diameter, it should be no problem.

The data sheet didn't say. I just read it on the URL you posted.

Well, I learned the art of cable cutting while working on radio towers in Smog Angeles. We're on top of a mountain and nobody remembered to bring a bolt cutter. The rigging was 3/16" and 1/4" galvanized wire rope. I tried to cut it with a hack saw. Bad idea. Someone found an abrasive disk grinder which chewed through the cable almost instantly. The next day, we came back with various cutoff devices. The little Dremel worked the best. Incidentally, don't try it with a dentists drill. The one we had spun at about 10,000rpm and did an impressive job of fragmenting the disk.

When I get rid of the cold I've caught, I'll dribble over to the shop and make a short video clip of me chopping through some cable. I won't have a PC Guardian cable, but I should have some cable somewhere.

Incidentally, cable locks are considered a bad joke in the bicycle mailing lists and web piles.

Video of Kryptonite bicycle lock opened with a Bic pen:

I've never seen one, but the photograph at the above URL seems to show a common aluminum Nyco-Press clamp.

I also have a Makita 9500D hand grinder, which methinks will also do the job.

Nice. Kinda like my Ramset gun. It claims it will do 14mm (0.55") diameter cable. I'm not sure I would want to hold that device when it cuts.

Drivel: Old business.

1. I didn't get a reply on GPS enabled phones for Cingular yet.
2. I never could figure out how to do a chi square randomness test on the various generated encryption keys.

About 40 years. Back when I was a juvenile delinquent.

Not much magic involved. See:

Here's a video of a bike theft that took only a few seconds.

Not so. One of the videos listed above showed the owner re-locking and re-opening the lock several times. However, it is possible to have that happen.

Holy Toledo, you be slow. Or, which class do you consider the Kensington to be in? I wasn't able to do it myself, but there are videos on that net purporting to be of various people opening the Kryptonite and Kensington locks in 10-15 seconds.

In my case, it has been established that the laptop disppeared within a _very_ short period. Two different people came to my office. One saw the laptop, the other did not. The thief either happened to have my same key, or some pick, or the "as seen on internet" method.

How about the patented tamper-resistant locking mechanism in the Notebook Guardian Ultra by PC Guardian (the actual product in my earlier post)?

Weight is less important than hardness. My bicycle lock is hardened, and I'm willing to bet that your Dremel would find it tough going.

Standard or Ultra? Hardness?

I'm still skeptical. I attacked an Ultra cable with a bolt cutter, and it took quite a long time to work through it.

Again, I'm referring to the Notebook Guardian Ultra by PC Guardian, not a lesser product.

The Dremel tool would be utterly useless without power, as in a storm at sea. I have Big stainless bolt cutters that easily do the job on heavy rigging. If you're really serious, there's a .22-powered cutter that makes it childs play, albeit with a fair amount of noise. ;)

Hardly. If the PC Guardian cable was as "hard" as a typical hasp lock, you could not bend the cable bundle. The reason you can't cut a hasp lock with a pair of bolt cutters is that the hasp lock is Rockewell surface hardness C65 while the bolt cutter is about C60. In order to make the cable bundle reasonably bolt cutter proof, the cable would need to be harder than the cutters. Anything that hard, even just on the surface, will be either stiff, brittle, or both. I couldn't find anything on the surface hardness of wire rope.

No. That's why I mentioned that the "steel core" might give my cutter problems. I won't know until I try it.

Well, if you wanna buy for me one of the PC Guardian cables, I'll be happy to try and destroy it.

Sorta. The bicycle cable lock and PC laptop cable lock are quite similar and share the same faults. The tubular locks, cable types, and Nyco-Press clamps have much in common.

Methinks the bicycle tubular lock is apparently similar to the tubular lock on the PC Guardian locking device. It's a bit difficult to tell from the web page, but the photos look similar if not identical.

This entire discussion is also rather speculative because apparently neither of us have seen the PC Guardian cable in question. I'll see what I can find at one of the local computer stores. Maybe they have something similar that I can inspect.

The typical laptop thief does not worry about operating under water or in a location devoid of power. If sufficiently blatant, they can just look for an unused AC outlet and plug in a 117VAC Dremel tool. Well, maybe not as most computer installation have every last AC outlet occupied. However, if this is an issue, there are air motors powered by compressed air that should work.

Drivel: One of my customers now has some type of locking device for their office laptop. The inspiration was that the thief walked through 3 offices full of employees, and walked out with a laptop without anyone taking notice. Methinks my Sonalert device would have been effective at waking up the employees that something was amis.

Sorry. I named the brand, as that is the only one that I have put to unfortunate test.

I used the Kensington religiously, even fanatically, and it failed me.

I now have a combination lock. I am not overly concerned about how well it would withstand an attack with bolt cutters or a dremel mototool, as I generally lock it to something that wouldn't tolerate real attack. I also think that a dremel cutting through steel would be nearly as loud as Jeff's Sonalert device.

I am disappointed that Kensington continues to sell a lock that has been the subject of lawsuits, and, for an additional fee, carries a guarantee against loss, but only if the lock is damaged.

Sure... _now_ I know that. ;-( How long have you known?

That's one of several that I found. Of course, you don't know what magic was involved with the filming of that clip.

There's another one at some bike show, where the guy walks up to a vendor, picks up a Kryptonite cable lock, takes a pen from some guy, whittles the end of the barrel, and does his work. The narration says all the yada-yada about no one knowing anyone, etc.

It occured to me later that the lock should be out of position after being cracked in this fashion. If I unlocked it with the key, I had to return to the locked position before I could remove my key. If I had opened it with something that didn't have that extra nub on the outside, the lock wouldn't have to return to the locked position. That would leave it unusable, since I wouldn't be able to insert my key to turn it back.

Of course -- I meant the cable -- "bicycle [cable] lock" was your term.

I don't care how it cuts "a typical cheap bicycle cable lock."

As I said, hardness matters.

So you're just assuming it's similar to "a typical cheap bicycle cable lock?"

Well, I learned the art of bolt cutting while doing marine maintenance.

Why bother? I grant you that it's easy to cut through "a typical cheap bicycle cable lock" (actually cable). That's not what I'm talking about.

Bad apple argument? ;)

Whatever.

More speculation. Let me know if and when you actually have something meaningful.

Experienced mariners know that electricity and water don't mix, and would never rely on an electric tool in an emergency. Battery tools are no better, because the batteries tend to be dead when you need them. This is why EPIEBs typically have sealed lithium batteries that are supposed to be replaced at regular intervals. But even so, experienced mariners want at least two EPIRBs because of the risk of battery failure.

It's not a problem.

Thanks for the updates.

Let me know if and when you do, or actually cut one of these cables. Until then...

Indeed.

Since you haven't any actual experience with the PC Guardian Ultra, I think that's an unwarranted assumption.

Did you miss the "mariner" part?

If it were really hard (Rockwell number), then it probably wouldn't bend and would be brittle. That's why they don't make cables out of fiberglass or Silicon Carbide. What they do with hasp locks is surface harden the metal. The core gives it tensile strength (Pascals or Newtons/m^2) while the hardened exterior gives it resistance from penetration by cutters. This works really well with solid hasp locks but is a problem with cables. The small diameter cable strands can be surface hardened, but they become very stiff and brittle. My guess(tm) is that the hardened core of the PC Guardian cable is probably the main line of defense and is probably surface hardened. Unfortunately, surface hardening does little against penetration by powered grinding, which works by heating the surface and ablating the heated material. Once the hardened surface material is heated to a sufficiently high temperature, it is easily penetrated. The smaller the kerf, the faster the cut. The solid bar type of hasp locks are more secure against powered grinding because they dissipate the heat more effectively than cable. With the cable strands, the heat is concentrated only in the strand being cut.

When it passes the New York street gang test, I'll be convinced.

I tried to get some references on the test results against powered tools such as a hand grinder. Not much to be found. The current model Kryptonite style locks lasted 2.5 to 10 minutes. I found no details on testing methods or results of attacking a cable lock with a powered hand grinder.

I did find some helpful advice for locking motorcycles in New York City:

1. What kind of locks should I use? As the saying goes, locks just keep honest people honest. A standard motorcycle fork lock can be defeated by an amateur thief in about the same time it takes you to use a key. A disk lock may deter joyriders but a professional can usually get through one in thirty seconds. Heavy chains and cable locks are more secure, but unless you chain the bike to something immovable, the pros will just throw it in a truck. Finally, chains and cables aren't absolute security either. Thanks to Tool Time Technology, a battery-powered grinder can get through most of them in a couple of minutes.

Google couldn't find anything on Tool Time Technology. I assume they sell battery operated hand grinders.

I call to your attention the video of the PC Guardian lock in question at:

For a quiet office environment, I probably would not use a hand grinder. I would look in the desk drawer, where I would expect to find the spare key. If that fails, I would split the partition wall and remove the anchor point. If that fails, I would steal the battery, charger, loose peripherals, and removeable drives, which are often worth as much as the laptop.

Now, back to the original topic of GPS tracking a stolen laptop. I just discovered that the animal tracking business has a suitable line of products. For example: |

None of these are from well known sources, at least not well known to me, so I don't know that the various actors are really doing what they claim to be doing. That's what I mean by magic. The magic of the movie production, not what is purportedly being accomplished.

That would be one of the staged videos, where either the actor is turning the lock back to the normal position in order to be able to do it again, or some editting magic is occurring. There would be no need for a thief to turn the lock back to the original position.

I couldn't find a patent number on their web pile. Searching the US Patent and Trademarks Office, I find nothing listed under PC Guardian.

Agreed. I've had to remove those from the surplus office desks I've bought. Two hits with a hammer and cold chisel and the epoxy just cracks off. However, I was referring to the anchor point show in the video. Those are only as secure as the partition connector, which can often be removed by simply lifting one partition. Some partitions do require a screwdriver to disassemble.

Agreed. It's time limited. The smash and grab method does not allow sufficient time to do anything elaborate. Instead of an expensive cable, a simple ty-wrap or leash would suffice to securing the laptop for a thief that only has seconds. However, as more and more time is available to perform the theft, opportunistic pilfery becomes a possibility.

I don't think a single solution will work for all circumstances. So far, we have my Sonalert alarm, PC Guardian cable lock, and GPS+Wi-Fi tracker. Each one has places where it will work just fine, and others were it will fail miserably.

Tensile strength correlates well to hardness.

Old news. Current Kryptonite products have a disc-style cylinder that performs very well in independent tests:

Canton, MA September 1, 2005 - Kryptonite, a brand in Ingersoll-Rand?s Security Technologies Sector, announced today that its line of security items with the disc-style cylinder have passed European testing agency standards in six countries. ART Foundation (Holland), FFMC (France), Sold Secure (UK), SRA (France), SSF (Sweden), Varefakta (Denmark) and VdS (Germany) have all passed Kryptonite?s products after vigorous tests. The enhanced KryptoLok line is the most recent to acquire certification with Sold Secure?s Bronze award for the product family. ... The ART Foundation rates products by grading them Level 1 to Level 4, which is the top ranking reserved for products offering theft resistance against all kinds of tools for at least five minutes. The New York Chain, both 168cm and 100 cm lengths, and the New York Noose have all been evaluated at 4+. The Stronghold ground anchor, Evolution Disc Lock (all colors), New York Lock and New York MC have all passed at Level 4. ...