Sharif Digital Repository

Popularity of data outsourcing and its consequent access control issues such as dynamism and efficiency is the main motivation of this paper. Existing solutions suffer from the potential unlimited number of user keys, inefficient update of policies, and disclosure of data owner’s access control policies. Using Chinese remainder theorem and proxy re-encryption together, in this paper, we propose an efficient access control enforcement mechanism based on selective encryption that addresses all the shortages. The overall architecture, required algorithms, and access control policy update are discussed. The mechanism is evaluated through simulation and, the given results are satisfactory  

It is quite common nowadays for clients to outsource their personal data to a cloud service provider. However, it causes some new challenges in the area of data confidentiality and access control. Attribute-based encryption is a promising solution for providing confidentiality and fine-grained access control in a cloud-based cryptographic system. Moreover, in some cases, to preserve the privacy of clients and data, applying hidden access structures is required. Also, a data owner should be able to update his defined access structure at any time when he is online or not. As in several real-world application scenarios like e-health systems, the anonymity of recipients, and the possibility of...