Lightweight and anonymous certificateless signcryption scheme for multi-receiver

This paper proposes an innovative certificateless signcryption scheme, which achieves lightweight computation and anonymity for both the sender and the receiver. By replacing the bilinear operation with elliptic curve scalar multiplication, the proposed scheme significantly reduces computational overhead, making it suitable for resource-limited devices. Furthermore, the scheme achieves the anonymity of both sender and receiver, by embedding the sender’s real identity within the set of disguises and concealing the receiver’s identity through pseudonyms. It also supports multiple receivers. It achieves a signcryption time of 1.134 ms, an unsigncryption time of 0.542 ms, and a ciphertext size of 280 bytes. Compared with some existing schemes that achieve sender or receiver anonymity and involve no pairing operations, the cost of signcryption and unsigncryption is reduced by 50% and 86% at most respectively. Through a formal security proof, we demonstrate that the proposed scheme ensures confidentiality and unforgeability.