I don't know what "234*527" is off the top of my head, but I know what the answer is if I need it. Imgur doesn't know who I am in a picture and wouldn't know the answer if they needed it (except for a massive & deliberate effort). Facebook, knowing my social graph, and knowing there is an untagged face in a picture, it is a trivial programming problem.
This is why I prefer privacy-by-design rather than privacy-by-policy, and why I think cryptography is awesome: I want to make these problems arbitrarily hard. :-)
Comments
I don't know what "234*527" is off the top of my head, but I know what the answer is if I need it. Imgur doesn't know who I am in a picture and wouldn't know the answer if they needed it (except for a massive & deliberate effort). Facebook, knowing my social graph, and knowing there is an untagged face in a picture, it is a trivial programming problem.
This is why I prefer privacy-by-design rather than privacy-by-policy, and why I think cryptography is awesome: I want to make these problems arbitrarily hard. :-)