Biblio

The Internet of Things (IoT) is enabling a new generation of innovative services based on the seamless integration of smart objects into information systems. Such IoT devices generate an uninterrupted flow of information that can be transmitted through an untrusted network and stored on an untrusted infrastructure. The latter raises new security and privacy challenges that require novel cryptographic methods. Attribute-Based Encryption (ABE) is a new type of public-key encryption that enforces a fine-grained access control on encrypted data based on flexible access policies. The feasibility of ABE adoption in fully-fledged computing systems, i.e. smartphones or embedded systems, has been demonstrated in recent works. In this paper we assess the feasibility of the adoption of ABE in typical IoT constrained devices, characterized by limited capabilities in terms of computing, storage and power. Specifically, an implementation of three ABE schemes for ESP32, a low-cost popular platform to deploy IoT devices, is developed and evaluated in terms of encryption/decryption time and energy consumption. The performance evaluation shows that the adoption of ABE on constrained devices is feasible, although it has a cost that increases with the number of attributes. The analysis in particular highlights how ABE has a significant impact in the lifetime of battery-powered devices, which is impaired significantly when a high number of attributes is adopted.

Access control is one of the most challenging issues in Cloud environment, it must ensure data confidentiality through enforced and flexible access policies. The revocation is an important task of the access control process, generally it consists on banishing some roles from the users. Attribute-based encryption is a promising cryptographic method which provides the fine-grained access, which makes it very useful in case of group sharing applications. This solution has initially been developed on a central authority model. Later, it has been extended to a multi-authority model which is more convenient and more reliable. However, the revocation problem is still the major challenge of this approach. There have been few proposed revocation solutions for the Multi-authority scheme and these solutions suffer from the lack of efficiency. In this paper, we propose an access control mechanism on a multi-authority architecture with an immediate and efficient attributes' or users' revocation. The proposed scheme uses decentralized CP-ABE to provide flexible and fine-grained access. Our solution provides collusion resistance, prevents security degradations, supports scalability and does not require keys' redistribution.