Optimized Ambiguous-Key ECC Signatures for Lightweight and Secure IoT Systems

In IoT constrained environments, traditional digital signatures struggle to acheive an effective balancebetween security, compactness, and computational efficiency. To overcome these constraints, we propose alightweight elliptic-curve signature scheme based on a dual-component private key (x, Q1) and two auxiliarycommitments, inspired by the Schnorr structure. The design introduces structural ambiguity in the secretkey, increasing resistance to key-recovery attacks while maintaining a lightweight and fast signature process.Experimental evaluation on NIST-standardized elliptic curves shows competitive performance: key generationranges from 11.6 ms to 232.1 ms, signing from 17.9 ms to 245.4 ms, and verification from 22.5 ms to 258.0 ms,with energy consumption below 2.8 μJ. The results confirm that the proposed scheme offers an effective a balanced compromise between compactness, runtime efficiency, energy usage, memory requirements, and practical security guarantees, making it suitable for distributed architectures and resource-constrained IoT devices.