Oblivious transfer 

Oblivious transfer (OT) is an important primitive in cryptography, especially in the area of secure multi-party computation. It was first introduced by Rabin [Rab81] in 1981 to establish an exchange of secrets based on the factoring problem. The cryptographic primitive in its simplest flavour i.e 1-out-of-2 OT is carried out between two parties, a sender and a receiver. The sender has two input messages M0 and M1 and a receiver has a choice bit c. At the end of the protocol the receiver is supposed to learn the message Mc and nothing else, while the sender is supposed to learn nothing. It is an essential cryptographic tool that can serve as a building block for almost all secure multiparty functionalities and other advanced cryptographic primitives.