Attribute-Based Encryption (ABE) is a powerful cryptographic tool that allows fine-grained access control over data. Due to its features, ABE has been adopted in several applications, such as encrypted storage or access control systems. Recently, researchers argued about the non acceptable performance of ABE when implemented on mobile devices. Indeed, the non feasibility of ABE on mobile devices would hinder the deployment of novel protocols and services--that could instead exploit the full potential of such devices. However, we believe the conclusion of non usability was driven by a not-very efficient implementation. In this paper, we want to shine a light on this concern by studying the feasibility of applying ABE on smartphone devices. In particular, we implemented AndrABEn, an ABE library for Android operating system. Our library is written in the C language and implements two main ABE schemes: Ciphertext-Policy Attribute-Based Encryption, and Key- Policy Attribute-Based Encryption. We also run a thorough set of experimental evaluation for AndrABEn, and compare it with the current state-of-the-art (considering the same experimental setting). The results confirm the possibility to effectively use ABE on smartphone devices, requiring an acceptable amount of resources in terms of computations and energy consumption. Since the current state-of-the-art claims the non feasibility of ABE on mobile devices, we believe that our study (together with the AndrABEn library that we made available online) is a key result that will pave the way for researchers and developers to design and implement novel protocols and applications for mobile devices.
@cite_1: Secure and fast distribution of software updates and patches is essential for improving functionality and security of computer systems. Today, each device downloads updates individually from a software provider distribution server. Unfortunately, this approach does not scale to large systems with billions of devices where the network bandwidth of the server and the local Internet gateway become bottlenecks. Cache-enabled Network (CN) services (either proprietary, as Akamai, or open Content-Distribution Networks) can reduce these bottlenecks. However, they do not offer security guarantees against potentially untrusted CN providers that try to threaten the confidentiality of the updates or the privacy of the users. In this paper, we propose Updaticator, the first protocol for software updates over Cache-enabled Networks that is scalable to billions of concurrent device updates while being secure against malicious networks. We evaluate our proposal considering Named-Data Networking, a novel instance of Cache-enabled overlay Networks. Our analysis and experimental evaluation show that Updaticator removes the bottlenecks of individual device-update distribution, by reducing the network load at the distribution server: from linear in the number of devices to a constant, even if billions of devices are requesting updates. Furthermore, when compared to the state-of-the-art individual device-update mechanisms, the download time with Updaticator is negligible, due to local caching.
Along the same line of studies, we also proposed a system for efficient software updates distribution, over untrusted distribution networks in @cite_1 . We used CP-ABE to guarantee flexible access control. In this work, we only provided evaluations measured on a laptop device with two 2.4 GHz Intel Core 2 Duo CPUs. Based on our experimental results, the CP-ABE encryption and decryption time for five attributes are 77.47 ms and 32.62 ms, respectively. We realized that not providing a proper feasibility assessment is a big limitation for this type of proposals. In this paper, we aim to fill this gap and pave the way for developing further solutions assuming the feasibility of ABE for mobile devices.