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The Data Encryption Standard (DES) is a system
developed for the U.S. government for use by the general public. The
DES algorithm, a combination of substitution and permutation, derives
its strength from repeated application of these two techniques, one on
top of the other, for a total of 16 cycles. The software algorithm
used in this benchmark was adopted from Eric Young's fast encryption
package. It performs rotation to align bits for simpler permutation.
As a result, this version of encryption requires only 42 operations
per substitution and permutation cycle. In contrast, the RAW
implementation takes advantage of the independence between each DES
encryption and decryption operation. It performs *n* encryptions or
*n* decryptions simultaneously, where *n* is the number of hardware
DES modules in the design. For each encryption, we use a lookup table
to bypass the shifting and substitution operations. As a result, an
individual hardware DES module is expected to achieve performance
similar to the best software solution and thus achieve an *O*(*n*)
speedup.