secau Security Research Centre, Edith Cowan University, Perth, Western Australia
Designing a fully secure (adaptive-predicate unforgeable and perfectly private) attribute-based signature (ABS), which allows a signer to choose a set of attributes in stead of a single string representing the signer‘s identity, under standard cryptographic assumption in the standard model is a challenging problem. Existing schemes are either too complicated or only proved in the generic group model. In this paper, we present an efficient fully secure ABS scheme in the standard model based on q-parallel BDHE assumption which is more practical than the generic group model used in the previous scheme. To the best of our knowledge, our scheme is the most efficient one among all the previous ABS schemes in the standard model. Moreover, our proposed scheme is highly expressive since it allows any signer to specify claim-predicates in terms of any predicate consists of AND, OR, and Threshold gates over the attributes in the system. ABS has found many important applications in secure communications, such as anonymous authentication system and attribute based messaging system.