Oblivious transfer impossible from noiseless channels If computationally unbounded parties $A$ and $B$ have only a noiseless channel between them, why is information-theoretic oblivious transfer impossible even for the passive cheating setting?
Intuitively, the noiseless channel makes the views of $A$ and $B$ almost identical except for the private randomness that $A$ and $B$ use. An unbounded passive cheater shouldn't be able to guess this randomness. How do we provably rule out some clever usage of private randomness that allows the sender to hide one of their bits and the receiver to hide her choice bit?
Information theoretic OT cannot be achieved because OT can compute any function in a two party setting, that is, OT is complete (meaning, it is among the hardest problems in its complexity class)  as shown by Kilian[0]. We know that there are functions that cannot be information theoretic securely in a two party setting[1]. Hence, information theoretic OT is impossible.
[0] https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.92.9265&amp;rep=rep1&amp;type=pdf
[1] https://eprint.iacr.org/2006/183.pdf