Final answer:
A collision occurs when two different inputs produce the same hash value. An attacker can exploit collisions to create malicious inputs that deceive a system or algorithm.
Step-by-step explanation:
The correct answer is d) Collision. A collision occurs when two different inputs produce the same hash value. An attacker can take advantage of hash collisions to create malicious inputs that fool a system or algorithm into performing unintended actions.
For example, consider a system that uses hash values to store passwords. If an attacker can find two different passwords that produce the same hash value, they can effectively gain access to another user's account without knowing the original password.
On the other hand, a birthday attack is a type of attack that takes advantage of the probability of collisions between random hash values. It is not specifically targeting hash collisions.