Practically Efficient Attribute-based Encryption for Compartmented Access Structures

Compartmented access structures (CASs) regulate the access control by requesting the consent of various compartments. Thus, they are particularly useful to Internet of Things or Wireless Sensor Networks applications with cloud support. The construction of practically efficient attribute-based encryption (ABE) schemes for CASs is faced with the fact that these access structures cannot be represented by Boolean formulas. The use of multilinear map based ABE schemes for general Boolean circuits is not only impractical but also suffers from the lack of secure multilinear map candidates. Also, the schemes based on lattice cryptography, even if they are secure, are highly inefficient in practice. We show in this paper that for CASs we can construct practically efficient ABE schemes based on secret sharing and just one bilinear map. The construction can also be applied to multilevel access structures.