ID-Based (t, n) Threshold Proxy Signcryption for Multi-Agent Systems

A (t, n) threshold proxy signcryption scheme allows t or more proxy signcrypters from a designated group of n proxy signcrypters to signcrypt messages on behalf of an original signcrypter. In this paper, an identity-based (t, n) threshold proxy signcryption scheme using bilinear pairings is proposed. Our construction is based on Baek and Zheng's pairing-based verifiable secret sharing scheme and Libert and Quisquater's identity-based signcryption scheme. As compared to the previous threshold proxy signcryption schemes, the key management problem in our scheme is simplified because of using identity-based cryptography. We also present an application of our scheme in multi-agent systems