Mega has launched
I just found a weird things on they ToS [1] ...8. Our service may automatically delete a piece of data you upload or give someone else access to where it determines that that data is an exact duplicate of original data already on our service. In that case, you will access that original data.Duplicate check, I get that. But, how do they do it? They say the files are encrypted on the browser, so if I upload file X and other user uploads X too, they can't know they're the same because both uploads are encrypted. So, they can check only for duplicates of the encrypted outcome of each file. But, wouldn't that be inefficient? Probability of collision in encrypted files is (AFAIK) really low, something like 2^(-N), N being the size of the file on bits... If I did it well, it'd be a collision probability of 7.458E-155 for a file of 1MB.[1] https://mega.co.nz/#termsEDIT: Added example.