Privacy-preserving multi-authority attribute-based encryption with dynamic policy updating in PHR

Abstract

As a new kind of patient-centred health-records model, the personal health record (PHR) system can support the patient in sharing his/her health information online. Attribute-Based Encryption (ABE), as a new public key cryptosystem that guarantees fine-grained access control of outsourced encrypted data, has been used to design the PHR system. Considering that privacy preservation and policy updating are the key problems in PHR, a privacy-preserving multiauthority attribute-based encryption scheme with dynamic policy updating in PHR was proposed. In the scheme, each of the patient's attributes is divided into two parts: attribute name and attribute value. The values of the user's attributes will be hidden to prevent them from being revealed to any third parties. In addition, the Linear Secret-Sharing Scheme (LSSS) access structure and policy-updating algorithms are designed to support all types of policy updating (based on "and", "or", and "not" operations). Finally, the scheme is demonstrated to be secure against chosen-plaintext attack under the standard model. Compared to the existing related schemes, the sizes of the user's secret key and ciphertext are reduced, and the lower computing cost makes it more effective in the PHR system.

Multiauthority Attribute-Based Encryption with Traceable and Dynamic Policy Updating

“…Since the QLZH scheme [28] and the YLLT scheme [29] are based on tree access structure, they do not have the functions of large attribute domain, dynamic access strategy update, and traceability. e YLMH scheme [30] can realize the dynamic access strategy update but does not support traceability; while the ZLML scheme [31] does not have the function of dynamic access policy update. Compared with the abovementioned related schemes, our scheme not only supports traceability, large attribute domain, and dynamic access policy update at the same time under multiple authorization agencies but also is based on the prime order bilinear group structure, which is more efficient.…”

“…In this section, we conduct a simulation experiment to evaluate the comparison of our scheme and the baseline algorithms (the simulation code is available in (https://github.com/monzxcv/ABE)). We select the scheme in [11] (YB scheme) and the scheme in [30] (YLMH scheme) as our baseline algorithms and run the experiments in five aspects: system initialization, key generation, data encryption, user decryption, and access strategy re-encryption. All the experiments are run on a 64-bit operating system of the Ubuntu 14.04 platform with a core 1.8 GHz processor and 4 GB RAM.…”

“…It can be seen that as the number of attributes increases, the cost of the YLMH scheme increases, and the cost of our scheme still keeps a constant value, so the larger the number of attributes, the more the advantage in our scheme. It can be seen from Figure 3 that the cost of the user private key generation time in all the three schemes increases linearly with the increase of YB [11] JZXL [27] QLZH [28] YLLT [29] YLMH [30] ZLML [31] Ours Order groups Prime Composite Prime √ √ √ √ Table 2: Performance comparison of multiauthority ABE schemes (https://github.com/monzxcv/ABE).…”

“…YB [11] SPB [32] YLMH [30] ZLML [31] Ours AA's public key attributes. is is because each attribute in the user's private key must be calculated accordingly.…”

Outsourced ciphertext-policy attribute-based encryption with partial policy hidden

“…But the bilinear pairing operations and modular exponentiations involved in the user testing phase and decryption phase increase linearly with the complexity of the policy. Yan et al 21 introduced a multi-authority ABE of partial policy hidden with dynamic policy updating. In the above schemes, the policy hiding is only to hide the attribute value, hence it is called semi-hidden policy.…”