The attack scenario where Chuck modifies messages between Alice and Bob is known as what type of attack?

The correct classification of the attack where Chuck modifies messages between Alice and Bob is known as a man-in-the-middle attack. In this type of attack, an unauthorized third party (in this case, Chuck) intercepts, monitors, or alters communication between two parties without their knowledge. The attacker effectively 'sits' between the two communicating entities, allowing them to manipulate the messages being exchanged or capture sensitive information.

This is particularly concerning in communications where data integrity and confidentiality are crucial. In a man-in-the-middle scenario, the attacker can pose as one or both parties, leading to various forms of data breaches or fraud. Understanding this type of attack is vital, as it highlights the importance of encryption and secure channels in communications to protect against such vulnerabilities.