Which statement about hash function output is true?

Which statement about hash function output is true?

• A. The output length varies with input.
• B. The output is a fixed-size digest.
• C. The output is the original input.
• D. The output is encrypted data.

Answer: (B)

Hash function output is a fixed-size digest. This means the algorithm always produces the same number of bits (or bytes) for any input, determined by the specific hash function you’re using (for example, SHA-256 always outputs 256 bits, regardless of input length). This fixed length is what makes digests convenient for quick comparisons and integrity checks. This digest is not the original input, and hashing is not encryption. A hash is designed to be one-way and not reversible; you shouldn’t be able to recover the original data from the digest. Also, changing even a tiny part of the input yields a markedly different digest (the avalanche effect), reinforcing its role in integrity verification.

Hash function output is a fixed-size digest. This means the algorithm always produces the same number of bits (or bytes) for any input, determined by the specific hash function you’re using (for example, SHA-256 always outputs 256 bits, regardless of input length). This fixed length is what makes digests convenient for quick comparisons and integrity checks.

This digest is not the original input, and hashing is not encryption. A hash is designed to be one-way and not reversible; you shouldn’t be able to recover the original data from the digest. Also, changing even a tiny part of the input yields a markedly different digest (the avalanche effect), reinforcing its role in integrity verification.