A New Efficient k-out-of-n Oblivious Transfer Scheme by means of Common Cipher

Abstract

The oblivious transfer protocol has a critical problem on the sender’s communication complexity. For this reason, we present a significant component called common cipher, which conceals all sender’s secrets. The sender can derive the corresponding decryption keys from a common cipher and different encryption keys. The advantage of the technology of common cipher is to greatly reduce the sender’s communication cost. Therefore, we employ our common cipher to develop an efficient OTnk . Our result is superior to all previous solutions in regard to the sender’s communication complexity. In our OTnk protocol, the sender cannot determine which k secret messages the chooser received even if the sender has unlimited computational power, and the chooser cannot get the other n − k secret messages if the factorization problem is hard. When k = 1 , we particularly suggest an efficient solution.