BACAS: A Blockchain‐Assisted Certificateless Aggregate Signature Scheme for Industrial Wireless Sensor Networks

ABSTRACT Rising concerns over data integrity and authentication in industrial wireless sensor networks (IWSNs) have driven the development of secure certificateless aggregate signature (CLAS) schemes. Several recent proposals have advanced this field; however, existing CLAS schemes remain vulnerable to coalition attacks, in which a group of compromised users collude to generate a valid aggregate signature from individually invalid signatures. These vulnerabilities allow malicious nodes to bypass security mechanisms and undermine system integrity. To address these limitations, this paper proposes a blockchain‐assisted CLAS scheme (BACAS) designed for IWSNs in industrial internet of things (IIoT) environments. BACAS employs blockchain to enable tamper‐resistant authentication while ensuring transparency and accountability in IIoT deployments. A formal security analysis under the random oracle model (ROM) demonstrates that BACAS is resilient against existential forgery under Type‐I, Type‐II, and Type‐III adversarial models. Furthermore, assuming a 1 MB block size and batch‐wise aggregation of 10 sensor readings per transaction, the framework supports approximately 9400 sensor readings per block, with a per‐reading storage cost of 111.5 bytes per node. Extensive performance evaluations show that BACAS achieves lower communication and computational overhead compared to recent related schemes while providing stronger security guarantees. In particular, BACAS reduces communication overhead by up to 67.33% for aggregate signatures generated by 10 sensors and computational cost by up to 16% for individual signature generation. These results demonstrate that BACAS enables secure, efficient, and scalable authentication, making it a practical solution for large‐scale IWSNs.