You're thinking of steganography [1], hiding the existence of information in an image (or other medium).
I'm aware of at least one case where Russian spies were known to have actually passed messages this way: "they embedded coded texts in ordinary-looking images posted on the Internet," according to the NYT [2].
Not quite. Having a QR code featured in a photograph isn't steganography since the existence of information is hardly hidden at all. Rather than hiding the information's existence what I'm considering here is how you could make it legally difficult to unequivocally prohibit spreading information that's in plain sight (think "Free Speech Flag" [1]).
Comments
You're thinking of steganography [1], hiding the existence of information in an image (or other medium).
I'm aware of at least one case where Russian spies were known to have actually passed messages this way: "they embedded coded texts in ordinary-looking images posted on the Internet," according to the NYT [2].
[1] http://en.wikipedia.org/wiki/Steganography
[2] http://topics.nytimes.com/top/reference/timestopics/subjects...
>You're thinking of steganography
Not quite. Having a QR code featured in a photograph isn't steganography since the existence of information is hardly hidden at all. Rather than hiding the information's existence what I'm considering here is how you could make it legally difficult to unequivocally prohibit spreading information that's in plain sight (think "Free Speech Flag" [1]).
[1] https://en.wikipedia.org/wiki/File:Free-speech-flag.svg