An efficient certificateless designated verifier signature scheme

To solve the key escrow problem in identity-based cryptosystem, Al-Riyami et al. introduced the CertificateLess Public Key Cryptography (CL-PKC). As an important cryptographic primitive, CertificateLess Designated Verifier Signature (CLDVS) scheme was studied widely. Following Al-Riyami et al. work, many certificateless Designated Verifier Signature (DVS) schemes using bilinear pairings have been proposed. But the relative computation cost of the pairing is approximately twenty times higher than that of the scalar multiplication over elliptic curve group. In order to improve the performance we propose a certificateless DVS scheme without bilinear pairings. With the running time of the signature being saved greatly, our scheme is more practical than the previous related schemes for practical application.