Hash digest property: what aspect is essential for integrity verification?

• A. Hashing produces a fixed-size digest used for integrity checks.
• B. Hashing provides reversibility and decryption.
• C. Hashing encrypts data for transmission.
• D. Hashing compresses data to hide content.

Answer: (A)

Integrity verification relies on a compact, fixed-length fingerprint of the data. When you hash, you produce a digest that uniquely represents the content; any change to the data will produce a different digest, so you can compare the received digest to the computed one and detect tampering. The fixed size makes storage and comparison straightforward, regardless of the input’s original size. Hashing isn’t about recovering the original data (not reversible) and it isn’t encryption (for confidentiality) or compression (which hides content). So the essential aspect for integrity checks is the fixed-size digest that acts as a reliable fingerprint to detect changes.