CompTIA Security+ (SY0-501) — Question 565

A cryptographer has developed a new proprietary hash function for a company and solicited employees to test the function before recommending its implementation. An employee takes the plaintext version of a document and hashes it, then changes the original plaintext document slightly and hashes it, and continues repeating this process until two identical hash values are produced from two different documents. Which of the following BEST describes this cryptographic attack?

Answer options

• A. Brute force
• B. Known plaintext
• C. Replay
• D. Collision

Correct answer: D

Explanation

The correct answer is D, Collision, as it refers to the scenario where two different inputs produce the same hash output, which is exactly what the testing employee is observing. The other options, such as Brute force, Known plaintext, and Replay, do not accurately describe the process of finding two distinct documents that yield identical hashes.