Georgia Institute of Technology
The growth of Smartphone capability has led to an explosion of new applications. Many of the most useful apps use context-sensitive data, such as GPS location or social network information. In this paper, the authors take this concept to its logical extreme with Efficient Mobile Oblivious Computation (EMOC), a technique that completely replaces garbled circuits with homomorphic operations on ciphertexts. They develop applications to securely solve the millionaire's problem, send tweets based on location, and compute common friends in a social network and then prove equivalent privacy guarantees to analogous constructions using garbled circuits. They then demonstrate up to 68% runtime reduction from the most efficient garbled circuit implementation. In so doing, they demonstrate a practical technique for developing privacy-preserving applications on the mobile platform.