Which statement describes a collision attack in cryptography?

Which statement describes a collision attack in cryptography?

• A. They are about securing network routes.
• B. They are about physical security.
• C. They find two different hashes that produce different outputs.
• D. They attempt to find two inputs that produce the same hash.

Answer: (D)

Collision attacks focus on hash functions and try to find two different inputs that yield the same hash value. The essence is to break the hash’s collision resistance by producing two distinct messages that produce an identical digest. This is why the statement describing the attack is the one that says two inputs produce the same hash, which can undermine data integrity and digital signatures if such collisions are found and exploited. In practice, cryptographers measure collision resistance and rely on hash functions like SHA-256 or SHA-3 to minimize the chance of collisions; historically, weaker hashes like MD5 and SHA-1 have had demonstrated collisions, illustrating why stronger algorithms are preferred. The other topics—network routing security or physical security—don’t address collisions in hash outputs, and the idea of two inputs producing different outputs does not describe a collision attack.

Collision attacks focus on hash functions and try to find two different inputs that yield the same hash value. The essence is to break the hash’s collision resistance by producing two distinct messages that produce an identical digest. This is why the statement describing the attack is the one that says two inputs produce the same hash, which can undermine data integrity and digital signatures if such collisions are found and exploited. In practice, cryptographers measure collision resistance and rely on hash functions like SHA-256 or SHA-3 to minimize the chance of collisions; historically, weaker hashes like MD5 and SHA-1 have had demonstrated collisions, illustrating why stronger algorithms are preferred. The other topics—network routing security or physical security—don’t address collisions in hash outputs, and the idea of two inputs producing different outputs does not describe a collision attack.