http://crypto.stanford.edu/craig/easy-fhe.pdf http://crypto.stanford.edu/craig/easy-fhe.pdf is a good summary of Craig Gentry's thesis (http://crypto.stanford.e

http://crypto.stanford.edu/craig/easy-fhe.pdf http://crypto.stanford.edu/craig/easy-fhe.pdf is a good summary of Craig Gentry's thesis (http://crypto.stanford.edu/craig/craig-thesis.pdf http://crypto.stanford.edu/craig/craig-thesis.pdf) and explains some of the limitations, for example why binary search in O(log n) time is not possible in a homomorphic scheme because it would necessarily reveal information about the untouched data.