Which security measure mitigates a man-in-the-middle attack of a REST API?

Password hashing protects passwords stored in a database from compromise but does not secure the communication channel itself against interception during an active transaction.

SSL (Secure Sockets Layer) or TLS (Transport Layer Security) certificates enable server authentication and encrypt the data exchanged between the client and the REST API server. This prevents attackers from intercepting, reading, or modifying the communication without being detected, effectively mitigating man-in-the-middle attacks.

Non-repudiation typically ensures that an action cannot be denied by the sender or receiver, often via digital signatures, but it doesn't primarily prevent the real-time interception and modification of data in transit.

Biometric authentication verifies a user's identity based on physical attributes, but it does not secure the actual communication channel over which the REST API operates.