Digital Signature To A Number Of Issues

Driven by commerce and all kinds of applications, Internet has developed rapidly. Now the Internet is ubiquitous and the human beings rely heavily on the Internet. The content on the internet is much richer than before and the value of the information flowing on Internet is more precious. The Internet brings great convenience and benefits to people's work and life. Meanwhile, the network information security has also become a common challenge in the world and it is also an important problem that must be well dealt with.Digital signature technology is one of the information security technologies. In the process of data transmission, digital signature can realize authentication, tamper-proof, spoofing-proof, data integrity protection and non-repudiation. At present, most network information security technologies depend directly or indirectly on digital signatures.The work of this paper can be summarized as follows:(1) The paper makes analysis of the progress and present situation in digital signature research, and it reviews the research achievements.(2) The paper describes a forward secure digital signature scheme based on the ElGamal by using one-way hash function to update signing key. The new signature scheme can realize authentication, verification, forgery-proof, non-repudiation functionality. Moreover, it has forward security. Even if an attacker obtains the signing key of current period, the signatures in previous periods are still secure. This scheme can minimize the signer's losses.(3) Designated verifier signature is the signature whose effectiveness is only validated by the designated verifier. The designated verifier cannot prove to others that the signature was signed by the original signer. This kind of signature can be used in the electronic auctions and voting systems. This paper introduces a designate verifier signature scheme based on the specified authentication certificate which can prevent forgery and transitivity.