A certificateless sanitizable signcryption scheme for air-ground collaborative transportation system

Air-ground collaborative transportation systems present a promising approach to improving safety and efficiency by facilitating real-time information sharing among UAVs, ground infrastructure, and intelligent vehicles through aerial networks. Yet, the reliance on open wireless networks exposes them to security threats such as eavesdropping, tampering, disruption and message forgery. Signcryption provides an effective cryptographic solution to mitigate these threats. However, existing methods still face challenges in security and efficiency, including: (1) key escrow risk and inefficiency stemming from centralized architectures; (2) active data leakage by malicious data senders. To address these issues, this paper introduces a Certificateless Sanitizable Signcryption scheme (AGC-CSS). In AGC-CSS, the generation of the private key requires contributions from both the user and the KGC. Even if the KGC is breached, the attacker cannot reconstruct the complete private key, which alleviates the risk of key escrow. Meanwhile, our scheme integrates encryption and signature into a single process, ensuring data confidentiality, integrity, and authenticity while maintaining high efficiency. Moreover, we designed a sanitization mechanism in which a sanitizer can re-randomize both the ciphertext and signature to prevent malicious senders. Formal security proofs and performance analyses indicate that the AGC-CSS scheme can resist various common attacks and applies to air-ground collaborative networks.