Research On Forward Secure Digital Signature Scheme

Digital signature is one of the main research contents of modern cryptography,which is widely used in information security,identity authentication,network office and e-commerce.Private key leakage in digital signature schemes can threaten signatures that have already occurred.In order to ensure the security of signatures before private key leakage,it is of great theoretical and practical significance to study forward-secure digital signature schemes.In this paper,several forward-secure digital signature schemes are studied.The work is as follows:(1)A forward secure digital signature scheme based on discrete logarithm is analyzed and improved.Firstly,a forward secure digital signature scheme based on discrete logarithm is analyzed by means of forgery attack,and it is pointed out that the scheme does not have forward security.Secondly,by embedding key in the signature and adding information of the current period,a difficult problem of solving discrete logarithm and modular square root is proposed.Finally,it is verified that the new scheme is not only forward-secure,but also improves the computational efficiency.(2)A forward secure digital signature scheme based on Euler criterion is analyzed and improved.The forward secure digital signature scheme based on Euler criterion proposed by Peng Renjie and others is studied by forgery signature.It is found that there is a security defect,that is,the signature s_i of the first valid period can be forged,which shows that the scheme is not anti-forgery.Then,an improved signature scheme is obtained by using positive integer.The new scheme optimizes the key generation,strengthens the relationship between signature and time interval i,as well as enhances the concealment of signature.At last,the correctness and forward security of the scheme are verified.