CREST Practitioner Security Analyst (CPSA) Practice

What is the function of the Diffie-Hellman protocol?

1. Data encryption

2. Key exchange

3. Data integrity verification

4. Access control mechanisms

The correct answer is: Key exchange

The Diffie-Hellman protocol is specifically designed for key exchange, allowing two parties to establish a shared secret over a public channel without requiring prior knowledge of each other's secret keys. This process involves each party generating a public-private key pair, sharing the public keys, and then using their own private key along with the received public key to compute a shared secret. The significance of this protocol lies in its ability to secure communications by enabling the two parties to derive a common key, which can subsequently be used for symmetric encryption. This method effectively addresses the challenge of exchanging keys securely, making it a foundational element in modern cryptographic practices. While other options such as data encryption, data integrity verification, and access control mechanisms are vital in cybersecurity, they do not encapsulate the primary function of the Diffie-Hellman protocol. Instead, those functions may rely on the secure keys established through Diffie-Hellman or similar key exchange mechanisms in order to operate effectively.