skip to main content


Title: MobiWear: A Plausibly Deniable Encryption System for Wearable Mobile Devices
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.  more » « less
Award ID(s):
1928349 1928331
NSF-PAR ID:
10279328
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
EAI International Conference on Applied Cryptography in Computer and Communications
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Li, Fengjun ; Liang, Kaitai ; Lin, Zhiqiang ; Katsikas, Sokratis K. (Ed.)
    Mobile computing devices have been used to store and process sensitive or even mission critical data. To protect sensitive data in mobile devices, encryption is usually incorporated into major mobile operating systems. However, traditional encryption can not defend against coercive attacks in which victims are forced to disclose the key used to decrypt the sensitive data. To combat the coercive attackers, plausibly deniable encryption (PDE) has been introduced which can allow the victims to deny the existence of the sensitive data. However, the existing PDE systems designed for mobile devices are either insecure (i.e., suffering from deniability compromises) or impractical (i.e., unable to be compatible with the storage architecture of mainstream mobile devices, not lightweight, or not user-oriented). In this work, we design CrossPDE, the first cross-layer mobile PDE system which is secure, being compatible with the storage architecture of mainstream mobile devices, lightweight as well as user-oriented. Our key idea is to intercept major layers of a mobile storage system, including the file system layer (preventing loss of hidden sensitive data and enabling users to use the hidden mode), the block layer (taking care of expensive encryption and decryption), and the flash translation layer (eliminating traces caused by the hidden sensitive data). Experimental evaluation on our real-world prototype shows that CrossPDE can ensure deniability with a modest decrease in throughput. 
    more » « less
  2. Lin, Jingqiang ; Tang, Qiang (Ed.)
    Nowadays, mobile devices have been used broadly to store and process sensitive data. To ensure confidentiality of the sensitive data, Full Disk Encryption (FDE) is often integrated in mainstream mobile operating systems like Android and iOS. FDE however cannot defend against coercive attacks in which the adversary can force the device owner to disclose the decryption key. To combat the coercive attacks, Plausibly Deniable Encryption (PDE) is leveraged to plausibly deny the very existence of sensitive data. However, most of the existing PDE systems for mobile devices are deployed at the block layer and suffer from deniability compromises. Having observed that none of existing works in the literature have experimentally demonstrated the aforementioned compromises, our work bridges this gap by experimentally confirming the deniability compromises of the block-layer mobile PDE systems. We have built a mobile device testbed, which consists of a host computing device and a flash storage device. Additionally, we have deployed both the hidden volume-based PDE and the steganographic file system-based PDE at the block layer of our testbed and performed disk forensics to assess potential compromises on the raw NAND flash. Our experimental results confirm it is indeed possible for the adversary to compromise the block-layer PDE systems when the adversary can have access to the raw NAND flash in real world. We also discuss practical issues when performing such attacks in practice. 
    more » « less
  3. We introduce MobiCeal, the first practical Plausibly Deniable Encryption (PDE) system for mobile devices that can defend against strong coercive multi-snapshot adversaries, who may examine the storage medium of a user’s mobile device at different points of time and force the user to decrypt data. MobiCeal relies on “dummy write” to obfuscate the differences between multiple snapshots of storage medium due to data encryption. By combining a tweaked thin provisioning with block- level encryption, MobiCeal supports a broad deployment of any block-based file systems on mobile devices. More importantly, MobiCeal is secure against side channel attacks which pose a serious threat to existing PDE schemes. A new fast switching mechanism is also introduced in MobiCeal to help users switch from the public mode to the hidden mode within 10 seconds. It is shown that the performance of MobiCeal is significantly better than prior PDE systems against multi-snapshot adversaries. 
    more » « less
  4. 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. 
    more » « less
  5. The Global Wearable market is anticipated to rise at a considerable rate in the next coming years and communication is a fundamental block in any wearable device. In communication, encryption methods are being used with the aid of microcontrollers or software implementations, which are power-consuming and incorporate complex hardware implementation. Internet of Things (IoT) devices are considered as resource-constrained devices that are expected to operate with low computational power and resource utilization criteria. At the same time, recent research has shown that IoT devices are highly vulnerable to emerging security threats, which elevates the need for low-power and small-size hardware-based security countermeasures. Chaotic encryption is a method of data encryption that utilizes chaotic systems and non-linear dynamics to generate secure encryption keys. It aims to provide high-level security by creating encryption keys that are sensitive to initial conditions and difficult to predict, making it challenging for unauthorized parties to intercept and decode encrypted data. Since the discovery of chaotic equations, there have been various encryption applications associated with them. In this paper, we comprehensively analyze the physical and encryption attacks on continuous chaotic systems in resource-constrained devices and their potential remedies. To this aim, we introduce different categories of attacks of chaotic encryption. Our experiments focus on chaotic equations implemented using Chua’s equation and leverages circuit architectures and provide simulations proof of remedies for different attacks. These remedies are provided to block the attackers from stealing users’ information (e.g., a pulse message) with negligible cost to the power and area of the design. 
    more » « less