Private Information Retrieval Based On Fully Homomorphic Encryption

We propose a construction of a single database private information retrieval system using fully homomorphic encryption. The construction results in a system with Ω(log2 n) communication complexity, and polylogarithmic computational overhead, in the size of the database. An improved construction is also proposed, which reduces the client’s communication overhead, and leaves open the possibility of reducing the total communication overhead. This results in a construction which has higher communication overhead than the current optimal system, but which is more computationally efficient.