Which hash algorithms are commonly used to verify forensic images, and why are they important?

• A. MD5, SHA-1, and SHA-256; they verify integrity, detect tampering, and ensure copies match the original
• B. SHA-3 only
• C. MD5 only
• D. CRC32 and MD5 for speed

Answer: (A)

Hash functions provide a fixed-size fingerprint of a digital image, creating a unique digest that should stay the same if the data does not change. In forensic workflows, you generate a digest of the original image at the time of acquisition and then re-calculate hashes on copies during transport, storage, and analysis to confirm they are exact bit-for-bit replicas. Using MD5, SHA-1, and SHA-256 is common because they give compact, widely supported digests that enable quick integrity checks and cross-tool compatibility. This practice helps verify integrity, detect tampering, and ensure copies match the original, which is crucial for maintaining the authenticity of evidence and the integrity of the chain of custody. While MD5 and SHA-1 have known weaknesses, combining them or favoring SHA-256 provides stronger protection against collisions and tampering than using a single weak hash. CRC32 is not cryptographic and can’t reliably detect tampering, so it’s insufficient for forensic accuracy, and SHA-3, though strong, isn’t as universally adopted for routine image verification as the SHA-2 family.