A certificateless signcryption with proxy re-encryption for practical access control in cloud-based reliable smart grid

Cloud computing has proven to be applicable in smart grid systems with the help of the cloud-based Internet of things (IoT) technology. In this concept, IoT is deployed as a front-end enabling the acquisition of smart grid-related data and its outsourcing to the cloud for data storage purposes. It is obvious that data storage is a pertinent service in cloud computing. However, its wide adoption is hindered by the concern of having a secure access to data without a breach on confidentiality and authentication. To address this problem, we propose a novel data access control scheme that simultaneously accomplishes confidentiality and authentication for cloud-based smart grid systems. Our scheme can enable the storing of encrypted smart grid-related data in the cloud. When a user prefers to access the data, the data owner issues a delegation command to the cloud for data re-encryption. The cloud is unable to acquire any plaintext information on the data. Only authorized users are capable of decrypting the data. Moreover, the integrity and authentication of data can only be verified by the authorized user. We obtain the data access control scheme by proposing a pairing free certificateless signcryption with proxy re-encryption (CLS-PRE) scheme. We prove that our CLS-PRE scheme has indistinguishability against adaptive chosen ciphertext attack under the gap Diffie–Hellman problem and existential unforgeability against adaptive chosen message attack under elliptic curve discrete logarithm problem in the random oracle model.