SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
The DES feedback mode block buffers the input and output blocks and contains all logic to implement the 3DES and various feedback modes. See the FIPS-81 document for details on the ECB, CBC, and CFB modes of operation.
By itself, the DES cipher core outputs data compliant for ECB encryption. However, most applications use DES with feedback. Feedback provides additional security by randomizing repeated patterns in the plain text, which could otherwise be exploited to attack the cipher text. The DES buffered engine supports ECB, CBC, and CFB modes of operations for the DES and 3DES algorithm.
3DES mode performs the DES algorithm three times on a single block and uses a different key for each invocation of the DES algorithm, greatly increasing security of the cipher text but at the cost of a 3x reduction in throughput. The DES buffered engine implements a 3DES logic wrapper around the 2-round DES core, enabling seamless 3DES encryption.