Research On Threshold Attribute-based Signature Schemes

With the development of cryptography, attribute-based cryptography has been more and more attractive as an extension of identity-based cryptography, because of its unique excellent quality. Threshold attribute-based signature scheme is an important part of attribute-based cryptography. Compared with other signature schemes, attribute-based signature scheme has many advantages, such as anonymity, more flexible tact. With the development of the Internet,information exchange becomes more frequent, threshold attribute-based signature schemes applied more widely. Recently, threshold attribute-based signature algorithm has achieved a series of results,but there are still some issues to be further studied and resolved,such as how to improve the theoretical security provability, how to design a flexible signature strategy,how to design multi-attribute agencies signature algorithm, how to design a signature algorithm with traceability ,etc.In this paper,we study several areas of threshold attribute-based signature schemes,including improving the theoretical security provability, designing a flexible signature strategy, and designing multi-attribute-based agencies signature algorithm. The main work of this paper can be summarized as the following three parts:Firstly,we design a new threshold attribute-based signature algorithm with provable security in the standard model. Recently, how to design threshold signature schemes with provable security has been a hot topic. However,most of the existing threshold signature schemes are provable security in random oracle model. As the first contribution of our thesis,we design a threshold attribute-based signature algorithm with provable security in the standard model, which is based on the hardness of Computation Diffie-Hellman problem.Secondly, we construct a new flexible strategy threshold attribute-based signature scheme. Usually, it is not easy to change the value of threshold in the standard attribute-based threshold signature scheme, which is not convenient in practice. As the second contribution of our thesis, we design a new attribute-based threshold signature scheme by introducing a tree structure, by which the signature policy becomes more flexible. Additively, this new threshold attribute-based signature scheme is provable security based BDH assumption in the standard model.Finally, we construct a new multi-agency attribute-based threshold signature scheme with provable security. Because the information of the real society is much more complicated and interactive, how to design multi-agency threshold attribute-based signature schemes becomes trendy. As the third contribution of our thesis, we design a new multi-agency threshold attribute-based signature scheme with provable security, which can effectively make up the over-reliance on the lack of central authority shortage of the threshold signature scheme with a single agency.