Signcryption is a new cryptographic primitive which simultaneously provides both confidentiality and authenticity. Previously, these two goals had been considered separately, with encryption schemes providing confidentiality and signature schemes providing authenticity. In cases where both were required, the encryption and signature operations were simply sequentially composed. In 1997, Zheng demonstrated that by combining both goals into a single primitive, it is possible to achieve significant savings both in computational and communication overhead. Since then, a wide variety of signcryption schemes have been proposed.
We begin by giving a formal definition of the signcryption, and then we discuss the need for signcryption, signcryption schemes, and consider their relative advantages and disadvantages. Subsequently we give an attention to the applications of signcryption finally, we look ahead at what future progress might be made in the field