I'm not sure exactly what technical problem you're alluding to, but it is possible, albeit very difficult to perform computations on encrypted files without the

I'm not sure exactly what technical problem you're alluding to, but it is possible, albeit very difficult to perform computations on encrypted files without the key. http://en.wikipedia.org/wiki/Homomorphic_encryption http://en.wikipedia.org/wiki/Homomorphic_encryption