A cycle-level recovery method for embedded processor against HT tamper

As the core of Internet of Things (IoT), embedded processors are being used more and more extensive. However, embedded processors face various hardware security issues such as hardware trojans (HT) and code tamper attacks. In this paper, a cycle-level recovery method for embedded processor against HT tamper is proposed, which builds two hardware-implementation units, a General-Purpose Register (GPRs) backup unit and a PC rollback unit. Once a HT tamper is detected, the two units will carry out fast recovery through rolling back to the exact PC address corresponding to the wrong instruction and resuming the instruction execution. An open RISC-V core of PULPino is adopted for recovery mechanism verification, the experimental results and hardware costs show that the proposed method could guarantee the processor restore from abnormal state in real time with a reasonable hardware overhead.