Digital Signature And Its Forward Security Research

With the advance of computer technique and the communication technique, the development of internet is impelled quickly. Based on network , the message service and application service developed swiftly. The information resource message service utilization ratio suficiently utilized the networ k communication service extremely great raise of capacity. Yet the internet in itself yet is not a security area at all, and the forceatack,hacker intrudes, virus and illegally grabs, so much network attacks emerge in an endless stream, and these are served challenge who wholly is severe as to the applications baseding on the network, and secure quality of message still more is directly affecing to based on network application service realization.The cryptology is the branch of learning to research informat ion security, and adopts themeans such as the message encipher, figure signature and identity au thority and key exchange and so on to safegrard secure quality of message in the network communication. Cryptosystem scheme is comprised of algorithm and key.According to Kerckho principle, the al gorithm is published to public.So the security of cryptosystem scheme fully depends on the security of key.Key exposure is fatal to a cryptosystem s cheme and the damge is unable to estimated.On esolution to the key-exposure problem is to improve the security of the secret key, for example secret sharing scheme, threshold cryptosystem, proactivese cret sharing scheme. Secret sharing scheme uses distributed storage to protect secret key. Thr eshold cryptosystem enhances the security of secret key with distributed computation.And proactive secret sharing scheme updates key frequently. There are some problem in there solutions, for example, new difficulty was in the solution, the cost of implementation is high, once secret key was lost the damages still can not be avoided.There are also so meother ways with hardware.Anot her way is forward-secure scheme, which we will discuss in this paper.To reduce the damage caused by key-exposure is the goal of forward-secure scheme.The scheme make enemy disable to forge signature be fore, then the damage was reduced . Forward-secure signature scheme modified primary model in common signature scheme.The notion "life cycle" was intro duced into new scheme and it is divided into several periods.The public key is kept unchanged in "life...