SHA-256 produces how many possible hash values?

• A. 2^128
• B. 2^64
• C. 2^512
• D. 2^256

Answer: (D)

SHA-256 produces a 256-bit digest. Since each bit can be 0 or 1, the total number of distinct hash values is 2 raised to the 256th power. In other words, there are 2^256 possible outputs, often shown as a 64-character hexadecimal string (each hex digit represents 4 bits, so 64 digits × 4 = 256 bits). This fixed 256-bit length defines the size of the output space and underpins the difficulty of finding collisions or preimages.