Performance of Some AES-Based AE and MAC Schemes Using Fixslicing on STM32 Microcontrollers

Message authentication codes (MACs) and authentication encryption algorithms (AEs) are widely used cryptographic primitives. OCB, OCBRA, PMACRA, and EliMAC are cryptographic schemes based on AES and reduced round AES. This work compares the schemes mentioned in a 32-bit ARM microcontroller. For efficiency, we implemented the AES round using a Fixslicing technique, which processes two blocks in parallel. Such characteristics are essential when the schemes allow parallelization between the AES calls. OCB and OCBRA were compared for authentication and encryption. OCBRA and EliMAC obtain similar performance for authentication, while OCB needs more clock cycles due to its initialization process. For encryption, OCBRA and OCB were practically identical.