What is the term for two inputs producing the same hash?

What is the term for two inputs producing the same hash?

• A. Collision Attack
• B. Birthday Attack
• C. Preimage Attack
• D. Hash Function

Answer: (A)

When two different inputs produce the same hash value, that situation is a collision. Hash functions map many possible inputs into a fixed-size output, so collisions must exist by the pigeonhole principle. An attacker who tries to deliberately find such a pair is performing a collision attack. The birthday attack is a probabilistic method to estimate how hard it is to find a collision, not the term for the event itself. The hash function is simply the function being used, not the phenomenon.

When two different inputs produce the same hash value, that situation is a collision. Hash functions map many possible inputs into a fixed-size output, so collisions must exist by the pigeonhole principle. An attacker who tries to deliberately find such a pair is performing a collision attack. The birthday attack is a probabilistic method to estimate how hard it is to find a collision, not the term for the event itself. The hash function is simply the function being used, not the phenomenon.