How to exchange (secret) keys
Manuel Blum · ACM Transactions on Computer Systems · 1983
KeysA protocol is presented whereby two adversaries may exchange secrets, although neither trusts the other.The secrets are the prime factors of their publicly announced composite numbers.The two adversaries can exchange their secrets bit by bit, but each fears the other will cheat by sending "junk" bits.To solve this problem we show how each of the two can prove, for each bit delivered, that the bit is good.Applications are suggested to such electronic business transactions as signing contracts and sending certified electronic mail.