Public Key Exchange

Question 1

What is the Protocol for Public Key Exchange (Diffie-Hellman)?

Answer 1

1. Alice and Bob agree on a prime number p and a number 2 <= g <= p - 2
2. Alice picks an α integer uniformly at random
3. Bob picks an integer β uniformly at random
4. Alice sends A = (g^α mod p)
5. Bob sends B = (g^β mod p)
6. Alice computes B^α mod p (= g^βα mod p)
7. Bob computes A^β mod p ( = g^αβ mod p)
8. Alice and Bob have computed the same element with is their shared secret