Q13Information Security Systems
Question
4 marks
Explain the Diffie-Hellman key exchange algorithm and its vulnerability.
Answer
Diffie-Hellman securely exchanges cryptographic keys over a public channel.
The Diffie-Hellman algorithm allows two parties to mutually agree on a shared secret key without ever transmitting the key itself. It relies on the discrete logarithm problem. Both parties agree on a large prime 'p' and a generator 'g'. They generate private values and exchange calculated public values. By combining their private value with the received public value, both arrive at the same shared secret. However, standard Diffie-Hellman is vulnerable to Man-in-the-Middle (MitM) attacks because it inherently lacks authentication.