The Research Of Linkable Ring Signature And Its Application In Electronic Voting

With the rapid development of network technology and informatization of human life unceasingly, the digital signature as an important authentication technology has been widely used in the field of information security. However ordinary digital signature is not always suitable for different application environment, therefore the special digital signature, such as threshold signature, group signature, blind signature, ring signature, proxy signature came into being.Ring signature causes the extensive attention of scholars since it is put forward, and the researchers design many ring signatures with different features, such as threshold ring signature, linkable ring signature, revocable anonymity, deniable ring signature and so on. Besides, these special ring signatures are constantly used in different network environment.This paper mainly studies linkable ring signature and its application in the electronic voting, main content includes:(1) The basic theory of the digital signature and related tools are introduced. First, this paper introduces some basic math knowledge such as Euler’s formula, Chinese remainder theorem and difficulty problems that are commonly used in the digital signature. Then, the paper discusses the secret sharing technology, digital signature and provable security theory. Finally, the general principle of ring signature is illustrated.(2) The existing linkable ring signatures are based on the discrete logarithm public key cryptosystems, and most of the schemes only have weak anonymity and strong correlation. This paper proposes a selectively linkable and convertible ring signature based on RSA public key cryptosystem. The signer can not only decide whether to correlate the different ring signature, on necessary occasions, also can cancel the anonymity of signature, converts ring signature to common digital signature. Finally, prove the scheme is existential unforgeability against adaptive chosen-plaintext under the random oracle machine model.(3) Add the threshold characteristics to the selectively linkable and convertible ring signature based on RSA that has been proposed, and design a new selectively linkable and convertible threshold ring signature based on RSA public key cryptosystem. The scheme can not only realize the function of a common threshold ring signature, but also has the characteristic of selectively linkability and anonymous convertibility. Finally, prove the scheme is existential unforgeability against adaptive chosen-plaintext under the random oracle machine model.(4) After analyzing the defects and shortages of the electronic voting scheme that have existed, this paper designs a secure and efficient electronic voting scheme by using linkable ring signature and blind signature in the condition of without any trusted center and anonymous communication channel. The scheme uses identity code to solve the problem of vote collision effectively and through introducing the information announcement mechanism solves the problem of the voters abstaining midway at any stage. In addition, the linkabale ring signature is applied in the stage of anonymous registration, so the efficiency of the scheme is improved greatly, suitable for large scale voting.