A Certificateless Aggregate Signature Scheme with Invalid Signatures Identification Resistant to Collusion Attacks for VANETs

We propose a certificateless aggregate signature scheme with an Agglomerative Identification Algorithm (AIA) for invalid-signature identification in VANETs. AIA encodes the ordered verification-point sequence as two signed-radix integers and lets the application server recover invalid positions locally after one ordered RSU–AS transfer. We additionally implemented a reproducible MIRACL signcryption comparison derived from the MyCLSC reference implementation. Across five independent runs, the n=100 all-valid batch averaged 367.2733 ms for vehicle signcryption, 110.8529 ms for RSU aggregate-signcryption construction, 653.6075 ms for the common AS unsigncryption stage, 1.8268 ms for AS aggregate verification, and 5.5825 ms for AIA identification. The fair DIV baseline reexecuted complete individual verification for all entries and required 650.9326 ms. At n=100 with random invalid signatures, AIA identification averaged 9.5142 ms, while full DIV required 650.2124 ms. Across 80 executable conditions, AIA recovered every injected invalid position without false positives or missed invalid entries, including the two-entry colluding-cancellation cases.