seems like something that can be bypassed by patching a couple jumps in asm with the help of IDA and a cup o' joe.
GIMP... and enjoy the coffee.
Exactly. Why is anything useful done, has to be done on a *nix? Oh wait ... that's how things GET DONE.
How printers and Photoshop detect and refuse to process images of currency
11–20 of 122 posts
Re: How printers and Photoshop detect and refuse to process images of currency
#12Re: How printers and Photoshop detect and refuse to process images of currency
#13When I was in college (99-2000ish, maybe?), one of my roommates was an art major with a graphic design bent, and he had this high end printer and would copy and print $1 bills and take 20 at a time over to the vending machines around the corner from our apartments once a week or so. After about a month of doing this, the machines disappeared. Of course, he's the same roommate who later got arrested for wire fraud and…
Given the cost of high quality ink and paper, one wonders how much less than $1 those bills cost to make.
Given that it was a decade and a half ago, and that even today's vending machine recognizers probably don't do much beyond making sure a few relatively gross features are present, I doubt the cost per counterfeit was all that close to $1.
Re: How printers and Photoshop detect and refuse to process images of currency
#14Re: How printers and Photoshop detect and refuse to process images of currency
#15Earlier quoted context omitted.
Given the cost of high quality ink and paper, one wonders how much less than $1 those bills cost to make.
Given that it was a decade and a half ago, and that even today's vending machine recognizers probably don't do much beyond making sure a few relatively gross features are present, I doubt the cost per counterfeit was all that close to $1.
"The primary method vending machines use to recognize the denomination of paper money is through a magnetic scan; paper currency is printed with magnetic ink, similar to the ink on the MICR line of a check, that makes it easily identifiable to machines with magnetic scanners. In addition, each denomination is marked with different fluorescent properties. Many vending machines and other machines that read paper currency use an ultraviolet light to scan the bill, read the fluorescent response and issue the appropriate credit."
Re: How printers and Photoshop detect and refuse to process images of currency
#16This 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.
That sounds like a decent addition to watermarking. It'd be difficult to crop out a watermark if you can't open the image in an image editor.
Re: How printers and Photoshop detect and refuse to process images of currency
#17Earlier quoted context omitted.
Given that it was a decade and a half ago, and that even today's vending machine recognizers probably don't do much beyond making sure a few relatively gross features are present, I doubt the cost per counterfeit was all that close to $1.
"The primary method vending machines use to recognize the denomination of paper money is through a magnetic scan; paper currency is printed with magnetic ink, similar to the ink on the MICR line of a check, that makes it easily identifiable to machines with magnetic scanners. In addition, each denomination is marked with different fluorescent properties. Many vending machines and other machines that read paper curren…
Presumably they were simpler-minded fifteen years ago; either that, or the art major's high-end printer was a lot higher-end than it seemed.
Re: How printers and Photoshop detect and refuse to process images of currency
#18Earlier quoted context omitted.
"The primary method vending machines use to recognize the denomination of paper money is through a magnetic scan; paper currency is printed with magnetic ink, similar to the ink on the MICR line of a check, that makes it easily identifiable to machines with magnetic scanners. In addition, each denomination is marked with different fluorescent properties. Many vending machines and other machines that read paper curren…
Presumably they were simpler-minded fifteen years ago; either that, or the art major's high-end printer was a lot higher-end than it seemed.
Or a third option: the story is fiction.
Re: How printers and Photoshop detect and refuse to process images of currency
#19Earlier quoted context omitted.
Exactly. Why is anything useful done, has to be done on a *nix? Oh wait ... that's how things GET DONE.
There's a sales pitch -- "Need to counterfeit money? Use Linux!"
It's been done, basically
Re: How printers and Photoshop detect and refuse to process images of currency
#20This 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.