ID-Based Signature Scheme with Tight Reduction

In an ID-based signature scheme (IBS), during the key extraction phase, the private key generator (PKG) selects a random element in the bilinear group as a part of private key of the signer. This idea can make the signer has many private keys for a given identity, which makes the key extraction more flexible. Based on this idea, an ID-based signature scheme is proposed. In this scheme, if necessary, the signer can sign a message using different private keys in different periods, which makes the signature scheme have a forward security property. Compared with the similar schemes, the new IBS has shorter signature and the least pairing operation, which shows the new IBS is more efficient than the other schemes of this kind. This IBS can be proved to be secure with tight reduction under the adaptive chosen-message attack and ID attack.