Suppose that Alice likes to use a secure cryptographic hash algorithm that produces a 256-bit output. However, for a particular application, Alice only requires a 128-bit hash. What can Alice do to obtain a 128-bit hash from the 256-bit output?
1) Truncate the 256-bit output to 128 bits
2) Pad the 256-bit output with zeros to obtain a 128-bit hash
3) Use a different cryptographic hash algorithm that produces a 128-bit output