Described is an execution unit for performing at least part of the Data Encryption Standard that includes a Left Half input; a Key input; and a Table input, as well as a first group of transistors configured to receive the Table input, perform a table look-up, and output data. The execution unit further includes a first exclusive-or operator having two inputs and an output that is configured to receive the Left Half input and the Key input. The execution unit also includes a second exclusive-or operator having two inputs and an output that is configured to receive the data output by the first group of transistors and to receive the output of the first exclusive-or operator. The execution unit also includes a third exclusive-or operator having two inputs and an output that is configured to receive the Left Half input and the data output by the first group of transistors.