SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
The DES cipher core implements the DES algorithm as specified in the FIPS 46-3. The core operates on the input block and performs the required substitution, shift, and mix operations. The core also applies the correct key-scheduling.
Inherently, considerable parallelism is possible with the DES algorithm. This is exploited in two ways. For high performance, the 64 bits composing the data block are processed concurrently (4-round implementation). For low gate count, resources are shared on both the main data and key paths (1-round implementation).
A fundamental component of the DES algorithm is the substitution box (S-Box). The S-Box provides a unique 4-bit output for each 6-bit input. The S-Box design is a primary factor for both performance and gate count. The DES Cipher Core has a standard lookup table S-Box that allows room for the synthesizer to optimize on timing or gate count.