An efficient identity-based signeryption scheme without bilinear pairings

Signcryption combines the functionalities of encryption and digital signing in a single logical step in order to obtain confidentiality, integrity, authentication and non-repudiation. It is more efficient than the sign-then-encrypt approach. Identity-based cryptography serves as an efficient alternative to the traditional certificate-based cryptosystems. The idea of identity-based cryptography is to enable a user to use any arbitrary string that uniquely identifies him as his public key. This paper proposes two new schemes. The first scheme involves a single recipient and the second is its extension in the multi-receiver setting. Both schemes outperform other schemes in literature as they do not involve any bilinear pairings in neither signcryption nor verification phases. Moreover, both satisfy various desirable security properties.