Oblivious Transfer with Complex Attribute-Based Access Control

摘要

In this paper, we present oblivious transfer with complex attribute-based access control policies. The protocol allows a database server to directly enforce "and" and "or" access control policies (c_1_1 ∧ c_1_2 ∧... c_1_n_1 )∨(c_2_1 ∧c_2_2 ∧... c_2_n_2 )∨...∨(c_t_1 ∧c_t_2 ∧... c_t_n_t) on each message in a database without duplication of the message as in Camenisch et al.'s AC-OT. To realize this protocol, we present the blind attribute-based encryption (ABE) scheme as a building block. Combining the blind ABE with a credential signature scheme, a generic construction for the oblivious transfer with complicated access control is presented. We also give a concrete scheme for the construction in which the policy is provided by an access tree which is represented by a formula involving "anrf(∧)" and "or(∨)" boolean operators.