Identity Based Threshold Proxy Signature

Identity-based (ID-based) public key cryptosystem can be a good alternative for certificate-based public key setting, especially when efficient key management and moderate security are required. In a (t, n) threshold proxy signature scheme, the original signer delegates the power of signing messages to a designated proxy group of n members. Any t or more proxy signers of the group can cooperatively issue a proxy signature on behalf of the original signer, but t − 1 or less proxy signers cannot. In this paper, we present an ID-based threshold proxy signature scheme using bilinear pairings. We show the scheme satisfies all security requirements in the random oracle model. To the best of authors’ knowledge, our scheme is the first ID-based threshold proxy signature scheme. keywords: ID-based signatures, threshold proxy signatures, bilinear pairings.