Using an ideal implementation of 1-2-OT for n-bit strings , construct 1-4-OT for n-bit strings. That is, the sender has 4 n-bit strings S0, S1, S2,S3, and the receiver has two bits bobi representing an integer c= 2bo + b1 € {0,1,2,3}. The receiver should get as output sc and neither player should learn anything else, except with negligible probability.