A Spectrum-Efficient Cross-Layer RF Distance Bounding Scheme

Figure 7

Proposed protocol design with a secure synchronization round. In the synchronization round, the verifier selects a nonce string and sends to the prover in a bit-by-bit fashion using PIE (pulse-interval encoding). The prover extracts the synchronization clock and string from the PIE data. The signed is sent to the verifier in the verification phase. Then, the verifier will check the signed to prevent that the attacker may use fake to cheat the prover before the synchronization round, thereby getting the prover’s response bits preemptively.