Authentication with public key Cryptography

Here A chooses a challenge -- a random number r and can verify that B is at other end using solely public information!

A Sends x

Decrypt x with dB and send back challenge

A Encrypts r using eB to give x

Send r

Only B could have sent back r

Alice is A

Bob is B

eB is public key of B

dB is B’s private key

Here A chooses a challenge -- a random number r and can verify that B is at other end using solely public information!