What does a fixed-size digest produced by a hash function help verify?

What does a fixed-size digest produced by a hash function help verify?

• A. A fixed-size digest used to verify data integrity.
• B. A mechanism to encrypt data for privacy.
• C. A method to compress data for storage.
• D. A means to identify the sender of data.

Answer: (A)

A fixed-size digest from a hash function is used to verify data integrity. The hash takes the data and produces a compact fingerprint that should be identical as long as the data hasn’t changed. If any bit is altered, the digest changes, so you can recompute and compare the digest at the destination to detect tampering or corruption. It isn’t used for hiding content via encryption, nor is it a data compression method, and it doesn’t by itself identify who sent the data—authentication would require a digital signature or similar mechanism.

A fixed-size digest from a hash function is used to verify data integrity. The hash takes the data and produces a compact fingerprint that should be identical as long as the data hasn’t changed. If any bit is altered, the digest changes, so you can recompute and compare the digest at the destination to detect tampering or corruption. It isn’t used for hiding content via encryption, nor is it a data compression method, and it doesn’t by itself identify who sent the data—authentication would require a digital signature or similar mechanism.