CPUs that process 128 bits as a single unit, compared to 8, 16, 32 or 64. As of 2015, there are no computers on the market that are inherently 128-bit machines. However, 128-bit registers are already used for floating point and parallel processing operations in 32-bit and 64-bit computers (see SSE). In addition, 128 bits are commonly used for encryption keys (see secret key cryptography). See bit specifications.