Post-Quantum Attribute-Based Encryption: Performance Evaluation and Improvement for Embedded Systems.

Ciphertext-Policy Attribute-Based Encryption (CP-ABE) is an encryption paradigm that embeds access control functionalities within ciphertexts. It has shown to be useful for protecting privacy and intellectual property in embedded systems, especially when confidential data is temporarily stored on untrusted cloud or edge servers. However, current CP-ABE ciphers are generally based on pairing mathematics, which is broken if attacked by large-scale quantum computers. Thus, these ciphers will not be secure anymore in the future. In this paper, we focus on a RLWE-based CP-ABE cipher (namely the scheme proposed by Gür et al. in 2019 on IEEE Trans. on Computers), which is believed to be resistant to quantum attacks, so it is a candidate replacement of pairing-based ABE schemes in the future quantum world. Specifically, we measure its performance in terms of processing time and memory with reference to two embedded applications: smart home privacy and automotive FOTA intellectual property protection. We also propose a method to improve the encryption efficiency by dividing it into a slow offline phase and a fast online phase.