Research On Forward-Secure Digital Signature

Digital signature is widely used in information security, identity authentication, data integrity, non-repudiation, anonymity and so on; especially in huge network and electronic business. Digital signature is one of the cryptology research directions. Thus, it is very impotant to design secure digital signature scheme.Practically, the main secure threat to signature scheme is: the private key of the signature scheme may be revealed, because of the system that the scheme depends on or the machine that the private key stored is broken. In traditional digital signature scheme, if the private key is revealed, its security is often compromised not only for subsequent uses of the private key, but also for prior ones.To solve the problem, forward-secure signature scheme was proposed. In forward-secure signature scheme, the operation is divided into time periods, with a different secret key for each time period. Each secret key is used to sign messages only during a particular time-period, while the public key for verifying signature remains unchanged. At the end of the each time period, signer uses the private key in current time period to get the one in next time period with key-update algorithm. In this way, if the private key in current time period is revealed, the signatures signed with the private keys used before the current time period are still valid. Based on the forward-secure signature scheme, David Galindo,Javier Herranz and Eike Kiltz (GHK) proposed the concept of identity-based forward-secure signature (IB-FSS) scheme, and they also gave the way to construct IB-FSS scheme. Then we look back the history of the research on forward-secure digital signature; introduce its definition, use and security model; analyse several famous forward-secure digital signature schemes. We also research on the characteristic and security model of identity-based forward-secure digital signature. The signature scheme of David Galindo, Javier Herranz, and Eike Kiltz (GHK) is also analyzed.For the weakness of GHK signature scheme, we propose a new identity-based forward-secure digital signature scheme based on RSA hard problem. We also analyse our scheme's security and efficiency.Finally, we present the development direction and new technology of the forward-secure signature, and point out the research direction in the future.