Abstract: Based on identity and bilinear pairing on the Elliptic Curve, a new multi-signcryption scheme is proposed. In this scheme, the user’s public key is his identity information, such as e-mail address, IP address, telephone number etc. This greatly decreases the cost of building and managing public key infrastructures; the expense of the users’ management of public-key and their certificates is avoided. By using bilinear pairing on the elliptic curve, this scheme can reach the equivalent security levels of the existing multi-signcryption schemes with a short length key and a small computational cost. Moreover, in this scheme, the original signcrypter using his private key decrypts the multi-signcrypted messages and verifies the validity of signcrypted messages and the order of multi-signcryption. Therefore, our multi-signcryption scheme based on identity and bilinear pairing efficiently achieves the cryptographic functions of multi-signcryption.

Key words: multi-signcryption, identity-based cryptosystem, bilinear pairing