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How printers and Photoshop detect and refuse to process images of currency

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Re: How printers and Photoshop detect and refuse to process images of currency

#111

Post by atmosx »

alextingle wrote: post #102
thirdsight wrote: post #22

Earlier quoted context omitted.

Similar. A friend of mine used an epson stylus printer (new on the market then) and a scanner to copy £20 notes. They were inserted into the change machine in the local gambling arcade type place. It was stupid enough to accept a single sided copy. Out popped pound coins. He now works for GCHQ which is funny. Edit: just to add that these change machines were really naff and obviously built by the lowest bidder.

> He now works for GCHQ which is funny. So he just moved on to even more serious crimes.

Well, mission accomplished ^_^

Re: How printers and Photoshop detect and refuse to process images of currency

#113

Post by atmosx »

logfromblammo wrote: post #20
wyager wrote: post #7

This is one of the things that made me really see the value of free software. I did verify experimentally that the Eurion constellation alone doesn't trigger photoshop's image rejection algorithm. I think it would be fun to distribute a bunch of images that false-positive the digimarc algorithms, just to mess with people.

They could add the detection to GIMP. But then that would reveal what the algorithm is. And that would allow specific strategies for producing false negatives or false positives. I'm still undecided about whether countermeasures to reverse engineering like this are useful or not in the long run.

These measures can stop a kid from counterfeiting. That's all they do. I'm sure in the process they could create some kind of sporadic troubles to designers which paid for the expensive software.

You can't possibly think that a criminal organization, with average tech resources, will have a hard time getting around this in a way or another.

Re: How printers and Photoshop detect and refuse to process images of currency

#115

Post by nappy-doo »

jjoonathan wrote: post #87
nappy-doo wrote: post #67

Earlier quoted context omitted.

And this is where you're wrong. Most detectors use a PIN diode or a phototransistor. Both work just fine with the SVM. Again, the security given in these detectors is SO good that even if I were to give you complete knowledge of the system, you can't beat them. I can't admit to having made counterfeits, but I can say that I've seen _all_ of them, and they do not work.

No, you haven't seen them all. That's a silly claim. And if the detector is what you say, I'm about 80% sure I know both why it worked so well and how to defeat it. As much as I wish I could make a bet with you and test this, I wish for trouble from the secret service even less, so I guess that's off the table.

I will tell you, with full knowledge of how they work, I am incapable of beating the machines for US bills. Some other currencies have better and worse protection (generally better), but I _know_ I cannot beat the machines in the US.

Re: How printers and Photoshop detect and refuse to process images of currency

#116

Post by geon »

saalweachter wrote: post #99
hatchoo wrote: post #89

Earlier quoted context omitted.

When I was in the States, some buddies had some Philippine Peso coins which weigh and are roughly the same size as quarters. They used a few if these to operate coin-based laundry machines.

The best part about this is, in small numbers, foreign currency just becomes domestic currency on the basis of similar appearance alone. You get a Canadian penny, you may not even notice, and even if you do, you don't care because the next guy won't either. The laundry/vending machines are an interesting case because there's a decent chance that the the vendors would just be taking bags of coins to the bank where, pr…

I was visiting Italy as a kid in the mid 90's. My dad would get pay phone token coins in the change, and apparently they were widely used interchangeably with the official coins.

http://en.wikipedia.org/wiki/Gettone

Re: How printers and Photoshop detect and refuse to process images of currency

#117

Post by clarry »

alextingle wrote: post #104
sounds wrote: post #93

Earlier quoted context omitted.

Furthermore, criminals are usually motivated enough to find something else that will do the job. The Photoshop anti-counterfeiting stuff? It just scares off amateurs with an inkjet who don't realize every page from their printer has a tiny coded tracking mark that identifies the printer, date, and time.

> every page from their printer has a tiny coded tracking mark that identifies the printer, date, and time. Another argument for free software.

For free hardware.

Re: How printers and Photoshop detect and refuse to process images of currency

#119

Post by csirac2 »

alextingle wrote: post #103
Zhenya wrote: post #86

Earlier quoted context omitted.

NAFF - At first I decided that it stood for 'Not Anything Fucking Fancy' then I googled it and realized its british slang:' https://www.google.com/search?q=naff

"realized" - at first I thought you couldn't spell, but then I googled it and realised that you're an American.

It turns out "-ise" is a French-ism, which we seem to have integrated in Australian English (blame Macquarie :-)

Re: How printers and Photoshop detect and refuse to process images of currency

#120

Post by jjoonathan »

nappy-doo wrote: post #115
jjoonathan wrote: post #87

Earlier quoted context omitted.

No, you haven't seen them all. That's a silly claim. And if the detector is what you say, I'm about 80% sure I know both why it worked so well and how to defeat it. As much as I wish I could make a bet with you and test this, I wish for trouble from the secret service even less, so I guess that's off the table.

I will tell you, with full knowledge of how they work, I am incapable of beating the machines for US bills. Some other currencies have better and worse protection (generally better), but I _know_ I cannot beat the machines in the US.

I wouldn't expect that someone who attributes the differentiating power of the machines to SVM would be able to beat them on any kind of bill.
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