Attribute-based encryption (ABE) is an advanced cryptographic tool and useful to build various types of access control systems. Toward the goal of making ABE more practical, we propose key-policy (KP) and ciphertext-policy (CP) ABE schemes, which first support unbounded sizes of attribute sets and policies with negation and multi-use of attributes, allow fast decryption, and are fully secure under a standard assumption, simultaneously.
The proposed schemes are more expressive than previous schemes and efficient enough.
We also implement our schemes in 128-bit security level and present their benchmarks for an ordinary personal computer and smartphones.
They show that all algorithms run in one second with the personal computer when they handle any policy or attribute set with one hundred attributes.