Which term describes a one-way function that reduces a message to a hash value used to verify message integrity?

Which term describes a one-way function that reduces a message to a hash value used to verify message integrity?

• A. Hash
• B. Encryption
• C. Hot Site
• D. Guidelines

Answer: (A)

A hash is a one-way function that takes input data of any size and produces a fixed-length digest. It reduces the message to a hash value, and because it’s one-way, you can’t practically recover the original message from the hash. This makes it ideal for verifying integrity: you compute the hash of the received message and compare it to the original hash; if they match, the message hasn’t been altered. Hash functions are designed to be deterministic, fast to compute, and resistant to preimage and collision attacks, which is why they’re used for integrity checks. Encryption, by contrast, is reversible and designed to protect confidentiality with keys, not to verify integrity by a hash. A hot site is a disaster-recovery facility, and guidelines are policy documents, neither of which relate to generating a hash for integrity verification.

A hash is a one-way function that takes input data of any size and produces a fixed-length digest. It reduces the message to a hash value, and because it’s one-way, you can’t practically recover the original message from the hash. This makes it ideal for verifying integrity: you compute the hash of the received message and compare it to the original hash; if they match, the message hasn’t been altered. Hash functions are designed to be deterministic, fast to compute, and resistant to preimage and collision attacks, which is why they’re used for integrity checks.

Encryption, by contrast, is reversible and designed to protect confidentiality with keys, not to verify integrity by a hash. A hot site is a disaster-recovery facility, and guidelines are policy documents, neither of which relate to generating a hash for integrity verification.