A Lightweight Identity-Based Secure Communication Scheme for In-Vehicle Networks

The increasing connectivity of intelligent vehicles exposes in-vehicle networks to message tampering, replay, impersonation, and unauthorized access. This paper presents an identity-based secure communication scheme that separates authenticated session establishment from established-session data protection. A trusted Key Generation Center provisions identity-bound private keys offline. The T-Box and a target ECU then perform mutual authentication, derive a shared session root key, and complete explicit bidirectional key confirmation. Direction- and purpose-specific subkeys are used with SM4-CTR and HMAC-SM3 to protect subsequent traffic. In the ProVerif symbolic model, all eleven secrecy and injective-correspondence queries return true under the stated assumptions. On the Windows/Python 3.12.7/UDP prototype, the median single-ECU handshake time is 287.560 ms, and the paired sender-plus-receiver processing median is 1.036 ms per 8-byte message. Under the stated unstuffed 500-kbit/s classical-CAN model, the selected profile requires 138.75 bits per message and yields 49.95% offered load for 18 ECUs at 100 messages/s per ECU. All 1200 frame-mutation trials were rejected without unauthorized plaintext release. These results characterize the symbolic model, host implementation, and analytical traffic model; they do not constitute target-ECU or physical-bus measurements.