Multi-Authority Attribute-Based Encryption With Attribute Verification Using Zero Knowledge Proofs

Abstract

Multi-authority Attribute-based Encryption (MAABE) schemes distribute the responsibility of managing the scheme attributes and attribute keys among several attribute authorities. However, MA-ABE schemes often assume that the attribute authorities are always fully trusted parties and lack authenticity checks. This paper proposes a Ciphertext-Policy MAABE scheme that incorporates a user-authority mutual authentication mechanism exploiting the properties of Zero-Knowledge Proofs. A batch version of the Schnorr protocol validates the authority identity and the possession of claimed attribute keys. The complete scheme is enhanced using asymmetric pairings to improve security and performance. Furthermore, outsourced decryption is considered to exploit the available computing resources under a fog-enabled IoT environment. The proposed scheme's analysis shows the overall construction's efficiency and, particularly, the efficiency and suitability of the mutual verification protocol.