Which tool verifies file integrity against a known baseline?

• A. md5sum
• B. sha256sum
• C. sha512sum
• D. cksum

Answer: (B)

Verifying file integrity against a known baseline is done by computing a cryptographic hash of the file and comparing it to the trusted baseline value. The SHA-256 hashing tool is used for this because SHA-256 produces a strong 256-bit digest that is resistant to collisions and tampering. MD5 is outdated and has known collision vulnerabilities, making it less suitable for security-sensitive integrity checks. A simple checksum tool like cksum uses a 32-bit CRC and isn’t cryptographically secure, so it’s not reliable for robust baseline verification. In practice, you store the SHA-256 digest of the file as a baseline and verify by running the tool with the -c option to check against that baseline. So the tool that verifies file integrity against a known baseline is sha256sum.