Certificateless Signcryption without Pairing

Certificateless public key cryptography is receiving significant attention because it is a new paradigm that simplifies the traditional PKC and solves the inherent key escrow problem suffered by ID-PKC. Certificateless signcryption is one of the most important security primitives in CL-PKC. However, to the best of our knowledge, all constructions of certificateless signcryption (CLSC) in the literature are built from bilinear maps which need costly operations. In the paper, motivated by certificateless encryption schemes proposed in [3, 21], we present a pairing-free CLSC scheme, which is more efficient than all previous constructions.