Towards Public Key Encryption Scheme Supporting Equality Test with Fine-Grained Authorization

In this paper we investigate a new category of public key encryption schemes which supports equality test between ciphertexts. With this new primitive, two users, who possess their own public/private key pairs, can issue token(s) to a proxy to authorize it to perform equality test between their ciphertexts. We provide a formulation and a corresponding construction for this primitive, and our formulation provides fine-grained authorization policy enforcements for users. With the increasing popularity of outsourcing data and computations to third-party service providers, this new primitive will be an important building block in designing privacy protection solutions supporting operations on encrypted data

Public Key Encryption Supporting Plaintext Equality Test and User-Specified Authorization

In this paper we investigate a category of public key encryption schemes which supports plaintext equality test and user-specified authorization. With this new primitive, two users, who possess their own public/private key pairs, can issue token(s) to a proxy to authorize it to perform plaintext equality test from their ciphertexts. We provide a formal formulation for this primitive, and present a construction with provable security in our security model. To mitigate the risks against the semi-trusted proxies, we enhance the proposed cryptosystem by integrating the concept of computational client puzzles. As a showcase, we construct a secure personal health record application based on this primitive

A Heterogeneous Systems Public Key Encryption with Equality Test in Smart City

Smart cities have been identified as areas which are urbanized and utilize diverse types of electronic data collection sensors that are used to oversee resources and assets efficiently. Smart meters are a unit of smart cities and they collect information about users and their consumption patterns. Consequently, the Internet of Things (IoT) being at a steady evolution has prompted multiple users into having their data collected from smart meters, stored on cloud servers. This is a way of saving costs and time involved in accessing the data. In spite of that, the cloud-assisted IoT faces privacy and security issues. This is as a result of the cloud servers possessing an untrusted nature. Due to this, it is essential for the data accumulated from the smart meters be encrypted hitherto outsourcing it to the cloud server. However, having encrypted data in the cloud server leads to a complication when it comes to accessing the data. For users who are on a different public key system, it becomes illogical for the users to first download the entire data on the cloud in order to access the required data. Therefore to resolve this issue, a heterogeneous systems public key encryption with equality test (HS-PKE-ET) scheme was proposed. The HS-PKE-ET scheme integrates certificateless public cryptography with equality test (CLC-ET) with the public key encryption with equality test (PKI-ET). This scheme allows an authorized cloud server to determine if two encryptions encrypted within heterogeneous systems possess equivalent messages. Basing on the random oracle model, the proposed scheme’s security is stated under the bilinear Diffie-Hellman assumption together with the computational Diffie-Hellman assumption. Ultimately the size of storage, computation complexities and properties with other related works are focused on and illustrations indicate our proposed scheme reflects a good performance

Public Key Encryption Supporting Equality Test and Flexible Authorization without Bilinear Pairings

In recent years, public key encryption with equality test (PKEET) has become a hot research topic in the cryptography community due to the advancement of cloud computing. Recently, Ma et al. proposed a new related primitive, called public key encryption with equality test supporting flexible authorization (PKEET-FA), and constructed a concrete scheme. In their proposal, four types of authorization were presented to support different authorization policies. However, their proposal is based on bilinear pairings which are time costing operations compared with modular exponentiations. In this paper, we present a new PKEET-FA scheme without bilinear pairings. Compared with the existing work, our proposal is more efficient

A heterogeneous signcryption scheme for smart grid with trusted multi-ciphertext equality test

Energy utilization rates have been largely improved thanks to the wide application of smart grids, thereby realizing the reliable, economic and efficient operation of the grids. However, such an application is also accompanied by many security issues. In response to the many problems within existing security schemes, such as not supporting the communication between heterogeneous cryptosystems, low security levels and a low data retrieval efficiency, a heterogeneous signcryption (HSC) scheme that supports a trusted multi-ciphertext equality test (MET) is proposed. The adoption of the HSC helps to identify secure communications from identity-based cryptosystems to certificateless cryptosystem, eliminates the certificate management problems in the traditional public key cryptography scheme, and ensures the confidentiality and authentication of power data. The introduction of the MET technology can avoid the high cost of equality test calculations after grouping ciphertexts in pairs. Using blockchain and smart contract technologies ensure the credibility of test results and eliminates the reliance on trusted cloud servers. Under the random oracle model, on the basis of the bilinear Diffie-Hellman, the computational Diffie-Hellman and the q-strong Diffie-Hellman problems, this paper proves that the scheme proposed herein meets the requirements of indistinguishability and one-way security under adaptive choice ciphertext attacks, and the unforgeability under the adaptive choice message attack. From the findings of the analysis, it has been shown that the proposed scheme satisfies more security attributes and requires lower computational overhead compared to similar schemes

Secure server-aided data sharing clique with attestation

National Research Foundation (NRF) Singapor