Attribute-based encryption (ABE) is a powerful primitive that has found applications in important real-world settings requiring access control. Compared to traditional public-key encryption, ABE has established itself as a considerably more complex primitive that is additionally less efficient to implement. It is therefore paramount that the we can simplify the design of ABE schemes that are efficient, provide strong security guarantees, minimize the complexity in their descriptions and support all practical features that are desirable for common real-world settings. One of such practical features that is currently still difficult to achieve is multi-authority support. Motivated by NIST's ongoing standardization efforts around multi-authority schemes, we put a specific focus on simplifying the support of multiple authorities in the design of schemes. Abstract: Code to separate paragraphs

Attribute-based encryption (ABE) is a popular type of public-key encryption that enforces access control cryptographically, and has spurred the proposal of many use cases. To satisfy the requirements of the setting, tailor-made schemes are often introduced. However, designing secure schemes---as well as verifying that they are secure---is notoriously hard. Several of these schemes have turned out to be broken, making them dangerous to deploy in practice.

Abstract Attribute-based encryption (ABE) cryptographically implements fine-grained access control on data. As such, data can be stored by an entity that is not necessarily trusted to enforce access control, or an entity that is not even trusted to have access to the plaintext data at all. Instead, access control can be externally enforced by a trusted entity. Additionally, some multi-authority variants of ABE—which do not have a central authority—can effectively and securely implement access control in multiple-domain settings. Furthermore, ABE is the only cryptographic approach to fine-grained access control that does not require an online trusted third party during access requests, and thus provides better availability properties. The actual realization of these theoretical advantages in practice depends on whether current state-of-the-art ABE schemes support the necessary core properties. Much progress has been made in the last two decades in pairing-based ABE schemes, owing to their versatility and efficiency. In fact, it is possible to support most core properties under strong security guarantees, while incurring acceptable storage and computational costs. It is therefore a good time to ask ourselves whether pairing-based ABE has reached its full practical potential. To answer this question, we provide a comprehensive systematized overview of various existing pairing-based ABE schemes and their core properties. We also investigate the relationship between these core properties and real-world access control requirements. We show that a few challenges remain, that must be overcome for ABE to reach its full potential as a mechanism to implement efficient and secure access control in practice.