Flexible Selective Data Sharing With Fine-Grained Erasure in VANETs

Vehicular ad hoc networks (VANETs), an increasingly significant technology in intelligent transportation systems, achieve information sharing, intelligent traffic flow control, and road condition prediction through data sharing between vehicles and other devices, enhancing traffic efficiency and driving safety. Nevertheless, there are still challenges to data sharing with respect to efficiency, flexibility, and security. In this paper, we build a flexible selective data sharing with fine-grained erasure (FSDS-FE) scheme in VANETs by introducing the novel cryptographic primitive called puncturable identity-based fine-grained proxy re-encryption and employing identity-based signature. In FSDS-FE, with the support for ciphertext transformation, the vehicles are able to flexibly share the outsourced traffic data with others. Different sharing content can be customized for various entities through fine-grained re-encryption to protect sensitive information. Furthermore, the outsourced traffic data could be erased in a fine-grained way by the vehicles. In order to optimize the efficiency and practicality of FSDS-FE, we construct an improved FSDS-FE scheme by designing a novel puncturable identity-based fine-grained broadcast proxy re-encryption with verifiable outsourced decryption scheme. Rigorous security analysis demonstrates that FSDS-FE can achieve the desired security requirements. The comprehensive performance evaluation shows that our schemes are efficient and practical enough in VANETs.