Homomorphic Encryption Based k-out-of-n Oblivious Transfer Protocols

Oblivious Transfer (OT) is an important cryptographic tool, which has found its usage in many crypto protocols, such as Secure Multiparty Computations [9], Certified E-mail and Simultaneous Contract Signing [20]. In this paper, the authors propose three k-OuT-of-n OT (OTn k) protocols based on additive homomorphic encryption. Two of these protocols prohibit malicious behaviors from both sender and receiver. They also achieve efficient communication complexity bounded by O (l ? n) in bits, where l is the size of the encryption key.