Threshold group signcryption scheme with high security

In order to meet the high security of group communication,by combining hyperelliptic curve cryptosystem with Schnorr's signature schemes,this paper proposed a high security group signcryption scheme with a(t,n) threshold signcryption and a(k,l) threshold verification.This scheme improved the security defects of Peng et al.,scheme and Wang et al.,scheme.It achieved proactive secret sharing of secrets of threshold signcryption and threshold unsigncryption by Desmedt et al.,secret redistribution protocol.The new scheme can avoid the attack of the evil information and provide the capability of detecting cheating and identifying the cheater besides the property which threshold group signcryption should have.It has lower communication cost and higher security which is especially suitable for solving security problems of the network with limited resource.