Which cryptographic function produces a 128-bit output?

Which cryptographic function produces a 128-bit output?

• A. MD5 hash
• B. SHA-1
• C. SHA-256
• D. BLAKE3

Answer: (A)

Hash output length is fixed for a given function, so identifying the digest size is key. MD5 produces a 128-bit digest (16 bytes). In contrast, SHA-1 yields 160 bits and SHA-256 yields 256 bits. BLAKE3 can produce outputs of various lengths, but its common/default digest is 256 bits, not 128. Since the question asks for a hash function that gives exactly 128 bits, MD5 is the match. (Note: MD5 is older and not recommended for security-sensitive hashing due to vulnerabilities.)

Hash output length is fixed for a given function, so identifying the digest size is key. MD5 produces a 128-bit digest (16 bytes). In contrast, SHA-1 yields 160 bits and SHA-256 yields 256 bits. BLAKE3 can produce outputs of various lengths, but its common/default digest is 256 bits, not 128. Since the question asks for a hash function that gives exactly 128 bits, MD5 is the match. (Note: MD5 is older and not recommended for security-sensitive hashing due to vulnerabilities.)