Several Digital Signature Scheme Algorithm Design

Along with the rapid development of information technology and the wide spread application of information equipment, the information age is full of unlimited business opportunities and convenience, but also full of hidden perils and dangers. For example, the network is vulnerable to attacks, resulting in the leakage of confidential information, the data being tampered with, ranging from enterprises, departments work to a standstill, even if a threat to national security and social stability. So guaranting information security has become one of the important issues. As information and digital signature authentication are important tools, information security has become a key mechanism. We do a detail study on digital signature. The main work as follows:1. Propurse a proxy signature scheme of designated receiver and proxy multi-signature scheme. It can resist the attack in document [18], and can apply widely in elections for the electronic, mobile communications, e-commerce, and other fields.2. Ring authenticated encryption scheme can be regarded as the combination of message encryption scheme and ring signature scheme, which has both encryption and ring signature's priority. Analyzing the Cao tianjies document, they find that the paper doesn't have the unconditional anonymity characteristic being including in a ring signature, so improve it and analyzing its'characters.3. Convertible ring signature is a ring signature that allows real signer through revealing some information about ring signature, convert ring signature into an ordinary signature. At the same time, prove that he is the real signer of the ring signature. This paper analysises the reference [20] detailedly and points out that the ring signature scheme based on EIGamal can't have convertible properties and doesn't have security. Improving it, propose a convertible ring signature.4. Document [21] is a new verifiable ring signature scheme based on Nyberg-Rueppel scheme, the scheme realizes the ring signature using the hash functioning merely. But there are a few flaws, so improve it, and get a verifiable ring signature scheme based on Nyberg-Rueppel, and analyse its'characters.5. Put forward a blind Nyberg Rueppel signature scheme with ID-authenticated and message recovery. It overcomes the blindness in blind signature scheme and have more use in some area.