ELSeM: An Efficient and Lightweight Security Mechanism for DSP

Digital Signal Processor (DSP) systems frequently manage highly sensitive data within critical sectors such as telecommunications, healthcare, and defense. However, DSP are vulnerable to attacks such as unauthorized access, reverse engineering and software vulnerabilities. To enhance the security of sensitive data without significantly increasing DSP hardware overhead, we propose ELSeM, an efficient and lightweight security mechanism specifically tailored for DSP. It utilizes Direct Memory Access(DMA) in conjunction with electronic fuse(efuse) and SM4 modules to encrypt/decrypt key data through data transmission process and obtain security permissions after successful key comparison. ELSeM offers several advantages: 1) Enables efficient encryption and decryption of data with variable pipeline stages of SM4 during DMA transfer process; 2) Lightweight, consumes minimal resources, which is specifically tailored for DSP; 3) Restrict arbitrary key access and employ redundancy backup which mitigates unauthorized chip access, thereby significantly enhancing chip security. We implement the ELSeM with RTL and conduct tape-out, verifying its security at chip level. The experimental results indicate that the hardware overhead of ELSeM is minimal, approximately 0.1%, and the activation or deactivation of SM4 functionality has virtually no effect on DMA throughout.