ACRSES – Advanced Cryptography on a Resource Scarce Embedded System

Abstract

This degree project aims to explore how a advanced cryptography can be applied on a resource scarce system. Specifically, the targeted system is a Raspberry Pi Pico and the advanced cryptography method is AES. Open-source AES implementations were used to achieve encryption, decryption and CMAC verification. Various tests cases were constructed to investigate the Raspberry Pi Pico’s performance under these test cases. The performance of the system was analysed by extracting data about the execution time. The data conclusively described a linear and predictable behaviour both when encrypting and decrypting 16 bytes thousands of times; when encrypting 4096 bytes; and when the encryption functions were interrupted by a load case. Encryption and decryption should theoretically take the same amount of time, however, the data showed decryption taking significantly longer; a problem that gets exacerbated with larger data sizes. Furthermore, the findings indicates that the performance of encryption and decryption functions remains unaffected by the available RAM.