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 adaptively secure under a standard assumption, simultaneously. Our schemes are more expressive than previous schemes and efficient enough. To achieve the adaptive security along with the other properties, we refine the technique introduced by Kowalczyk and Wee (Eurocrypt’19) so that we can apply the technique more expressive ABE schemes. Furthermore, we also present a new proof technique that allows us to remove redundant elements used in their ABE schemes. We 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.

基于属性的加密 (ABE) 是一种高级加密工具，可用于构建各种类型的访问控制系统。为了使 ABE 更加实用，我们提出了密钥策略 (KP) 和密文策略 (CP) ABE 方案，它们首先支持无限大小的属性集和具有否定和多次使用属性的策略，允许快速解密，并且同时在标准假设下是自适应安全的。我们的方案比以前的方案更具表现力并且足够高效。为了实现自适应安全性以及其他属性，我们改进了 Kowalczyk 和 Wee (Eurocrypt'19) 引入的技术，以便我们可以应用该技术更具表现力的 ABE 方案。此外，我们还提出了一种新的证明技术，允许我们删除 ABE 方案中使用的冗余元素。我们以 128 位安全级别实施我们的方案，并为普通个人电脑和智能手机展示了它们的基准。他们表明，当所有算法处理具有一百个属性的任何策略或属性集时，所有算法都会在一秒钟内在个人计算机上运行。