Study And Design Of Several Proxy Cryptographic Schemes

With the rapid development of computer network and information technology, how to effectively solve the problem of authorization transfer in digital signature and cipher decryption has become more and more concerned. Proxy cryptography is just the most effective and potential technology to solve such problems. It mainly consists of two parts: proxy signature and proxy cryptosystem. The former generally studies the problem of authorization in digital signature, while the latter concerns more on authorization in cipher decryption. In recently years, many specialists both at home and abroad have made deep research on proxy cryptography. However, as far as we know, the research on proxy cryptography's formal security is not ideal enough. Thereby our point in this thesis is to study and design a series of proxy cryptography schemes systematically via formalization means. Our main achievements are as follows:1. From the point of view of correspondence's bandwidth, the research on short proxy signature is quite significant. Nevertheless, relative study is not broad at present. Thus primarily we design a series of short proxy signature schemes via BLS short signature scheme, including basic short proxy signature scheme, short multi-proxy signature scheme and short threshold proxy signature scheme. We provide provable security proof under random oracle model for each of our schemes.2. Many specialists have made a deep study on the problem of proxy signer's privacy protection. But all of their results are not as good as enough. Thus we link proxy signature with ring signature and propose a new proxy ring signature scheme to solve it. Again we also provide provable security proof under random oracle model for it.3. In some circumstances proxy signer can only sign messages for original signer only once. As far as we know, ID-based one time proxy signature scheme has not been studied yet. Thus in this thesis we give a formal definition of ID-based one-time proxy signature scheme and propose the first ID-based one time proxy signature scheme with provable security.