Secure access of multiple keywords over encrypted data in cloud environment using ECC-PKI and ECC ElGamal

Abstract

Data owners find it more comfortable and cost-effective to outsource the data set over the cloud server. Which in fact provides the more dynamic set of quality services with pay per use cost. And also reduces computing complexity at data owner and user side. While using this privilege we assume the nature of cloud server as honest but curious. Outsourced sensitive data over third-party server increases grave privacy anxieties, which leads to the common solution like, encryption of dataset with confidentiality of searchable indexes. Operating over encrypted data along with maintenance of query privacy has some serious concerns. The modern data user concerns are wide, ranging from privacy, search efficiency to least computational and memory load. In this paper, ECC based PKI is used for key management between multiple data owners and authorize users. Elliptic Curve ElGamal (ECEG) is first time used over searchable indexes, which allows efficient ranking of documents due to its additive homomorphic nature. Apart from security, Elliptic Curve Cryptography (ECC) is also known for its suitability for better PKI compatibility and support for easiness while encryption and decryption. Additional concerns of the least computational load at user side are taken care by keeping most of the operations at cloud server side. The analysis shows the proposed ECC based scheme supports multi-keyword search, the correctness of the scheme and flexibility towards data set modification. In future, this approach can be beneficiary to the user for maintenance of privacy and security of data on the cloud environment.