Diffie–Hellman Protocol

Watched the video from Terence Tao and heard of interesting term, Diffie Hellman Protocol.

If A and B are strangers and want to exchange secrets.

A send B a box with a lock LA.

B can not open it so B add one more lock to the box with a lock LB sent it back

A get the box with two locks, unlock the lock LA, and sent it back to B again.

B get the box with its own lock LB, unlock it, finally he get the message.

Interesting thought.!!!!