Paper 2020/460

A Bunch of Broken Schemes: A Simple yet Powerful Linear Approach to Analyzing Security of Attribute-Based Encryption

Marloes Venema and Greg Alpár

Abstract

We present a linear approach to analyzing security of attribute-based encryption (ABE). We use this approach to algebraically break eleven schemes: two single-authority and nine multi-authority attribute-based encryption (MA-ABE) schemes. These latter attacks illustrate that mistakes are made in transforming single-authority schemes into multi-authority ones. Our linear approach is not only useful in the analysis of existing schemes, but can also be applied during the design and verification of new schemes. As such, it can prevent the design of insecure MA-ABE schemes in the future.