Elliptic Curve Signcryption with Encrypted Message Authentication and Forward Secrecy

Summary This paper presents a comprehensive signcryption scheme based on elliptic curves. In addition to the message confidentiality, nonrepudiation and unforgeability, the proposed scheme achieves forward secrecy and encrypted message authentication needed by firewalls. A judge can resolve disputes by directly verifying the sender’s signature on signcrypted messages without help from the sender and without decrypting the message. Firewalls can securely filter signcrypted messages passing through them without having to do full unsigncryption to verify the sender’s identity. If the sender’s long-term key is compromised, the previous messages signcrypted with that key remain confidential. Elliptic curves are used for their security, key size and bandwidth advantages. The proposed scheme combines these security properties with savings in computational complexity and bandwidth overhead.