Escrow-free attribute based signature with constant-size for the internet of things

Attribute based signature (ABS) provides a promising solution for anonymous authentication. However, numerous prevailing ABS algorithms are ill-suited for anonymous authentication in the Internet of Things (IoT), due to problems such as key escrow, high computational overhead, inflexible access policies, and vulnerability to collusion attacks. Considering these shortcomings, we present an escrow-free attribute based signature with constant-size signature for IoT. Our proposal uses the linear secret-sharing scheme (LSSS) and the notion of certificateless cryptography to restrict the authorities of each attribute authority and the system authority. In addition, it generates a constant-size signature and achieves high verification efficiency by aggregating attribute keys. Theoretical analyses demonstrate that our proposal achieves anonymous authentication and is provably secure under the standard model. Simulation experiments show that the execution time of our algorithm is less than 50 ms to run during both the signature and verification phases, making it well-suited for applications with limited resources.