Search for: All records

Modern mobile devices are increasingly used to store and process sensitive data. In order to prevent the sensitive data from being leaked, one of the best ways of protecting them and their owner is to hide the data with plausible deniability. Plausibly Deniable Encryption (PDE) has been designed for such purpose. The existing PDE systems for mobile devices however, have suffered from significant drawbacks as they either ignore the deniability compromises present in the special underlying storage media of mobile devices or are vulnerable to various new attacks such as side-channel attacks. In this work, we propose a new PDE system design for mobile devices which takes advantage of the hardware features equipped in the mainstream mobile devices. Our preliminary design has two major component: First, we strictly isolate the hidden and the public data in the flash layer, so that a multi-snapshot adversary is not able to identify the existence of the hidden sensitive data when having access to the low layer storage medium of the device. Second, we incorporate software and operating system level deniability into ARM TrustZone. With this TrustZone-enhanced isolation, our PDE system is immune to side-channel attacks at the operating system layer. 

Mobile computing devices are widely used in our daily life. With their increased use, a large amount of sensitive data are collected, stored, and managed in the mobile devices. To protect sensitive data, encryption is often used but, traditional encryption is vulnerable to coercive attacks in which the device owner is coerced by the adversary to disclose the decryption key. To defend against the coercive attacks, Plausibly Deniable Encryption (PDE) has been designed which can allow the victim user to deny the existence of hidden sensitive data. The PDE systems have been explored broadly for smartphones. However, the PDE systems which are suitable for wearable mobile devices are still missing in the literature. In this work, we design MobiWear, the first PDE system specifically for wearable mobile devices. To accommodate the hardware nature of wearable devices, MobiWear: 1) uses image steganography to achieve PDE, which suits the resource-limited wearable devices; and 2) relies on various sensors equipped with the wearable devices to input passwords, rather than requiring users to enter them via a keyboard or a touchscreen. Security analysis and experimental evaluation using a real-world prototype (ported to an LG G smartwatch) show that MobiWear can ensure deniability with a small computational overhead as well as a small decrease of image quality.