Forward-secure unidirectional threshold proxy re-signature

To reduce the loss caused by the leakage of the re-signature key,a scheme of forward-secure unidirectional threshold proxy re-signature(FSTPRS) was proposed in this paper.The re-signature key was updated in each period by one-way function while the public key remains fixed.As a result,even if the current re-signature key was exposed,the adversary could not recover the re-signature key before the current time period or forge any signatures pertaining to the past.The security of scheme was proved in the standard model.The analysis result shows that it is robust and secure against the existing forgery under the adaptive chosen message attack,under the condition of the computational Diffie-Hellman.