Threshold signcryption scheme based on elliptic curve cryptosystem and verifiable secret sharing

In this paper, we present a signcryption scheme based on elliptic curve cryptosystem, which can perfectly integrate digital signature with public key encryption. Then, based on the proposed signcryption scheme, we design a verifiable (f, n) threshold signcryption scheme. This threshold signcryption scheme not only has the advantages of threshold scheme but also has the functions that can prevent the cheating of trusted center, the cheating of participants each other, and the cheating that participants modify their private keys. In the message recovery phase, only the specified recipient can recover the signcryption message. Our proposed scheme has small communication cost, and this cost becomes smaller by compressing the points over elliptic curve.