Digital evidence validation involves using a hashing algorithm utility to create a binary or hexadecimal number that represents the uniqueness of a data set. Which of the following hash algorithms produces a message digest that is 128 bits long?

• A. CRC-32
• B. SHA-1
• C. SHA-512
• D. MD5

Answer: (D)

Hash algorithms produce a fixed-size digest, and the question asks which one yields a 128-bit result. MD5 outputs a 128-bit digest (16 bytes, commonly shown as 32 hexadecimal characters). In comparison, CRC-32 gives 32 bits, SHA-1 gives 160 bits, and SHA-512 gives 512 bits. So MD5 is the correct choice for a 128-bit message digest. Note that MD5 is no longer recommended for security-critical tasks due to vulnerabilities, and stronger hashes like SHA-256 are preferred for modern digital evidence validation, but the question is focused on the digest length.