Dual-server certificateless public key encryption with authorized equality test for outsourced IoT data

Abstract

The Internet of Things (IoT) devices with restricted storage and computing sources are unable to store and handle massive data at local. A promising method is to engage some cloud server for maintaining outsourced encrypted IoT data and responding user request, in the meantime, the privacy of outsourced data can be protected. Existing encryption techniques with equality test allow the authorized cloud server to compare encrypted data and perform data classification. However, these schemes in the single server model cannot resist internal keyword guessing attacks. Also, the existing schemes in public key setting confront the burden of maintaining public key certificates, and the ones in identity-based setting face the key escrow problem. To address these issues, this paper proposes a dual-server certificateless public key encryption scheme supporting authorized equality test (DS-CL-AET) in bilinear groups. Security analysis indicates that the proposed DS-CL-AET scheme offers confidentiality protection for outsourced ciphertext and authentication tokens. Performance analysis demonstrates the practicality of our DS-CL-AET scheme in securing outsourced IoT data in clouds.