What mechanism is used in replay protection?

Replay protection aims to prevent the unauthorized repeated use of a transaction or communication. One effective mechanism for achieving this is through the use of sequence numbers and timestamps.

Sequence numbers are unique identifiers assigned to each message or transaction, ensuring that each one is distinct. When a transaction is sent, it includes a sequence number that must be used only once. If an attacker attempts to intercept and resend the transaction at a later time, the sequence number will indicate that it’s a duplicate and should be rejected.

Timestamps complement this by indicating when a message was created. By checking the timestamp, systems can determine whether a transaction is still valid or if it has expired, thus rejecting old messages. This dual approach effectively mitigates the risks associated with replay attacks, ensuring the integrity and timeliness of the communication.

The other options do not specifically address replay protection. High-level crystal encryption is related to securing data but does not inherently prevent replay. Dynamically changing user passwords enhances security but is not directly related to preventing replay attacks. Biometric verification improves authentication security but does not serve as a mechanism for detecting or preventing replay scenarios.