Use of mobile phones today has become pervasive throughout society. A common use of a phone involves calling another person using VoIP apps. However the OSes on mobile devices are prone to compromise creating a risk for users who want to have private conversations when calling someone. Mobile devices today provide a hardware-protected mode called trusted execution environment (TEE) to protect users from a compromised OS. In this paper we propose a design to allow a user to make a secure end-to-end protected VoIP call from a compromised mobile phone. We implemented our design, TruzCall using Android OS and TrustZone TEE running OP-TEE OS. We built a prototype using the TrustZone-enabled Hikey development board and tested our design using the open source VoIP app Linphone. Our testing utilizes a simulation based environment that allows a Hikey board to use a real phone for audio hardware.
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TruZ-Droid: Integrating TrustZone with Mobile Operating System
Mobile devices today provide a hardware-protected mode called
Trusted Execution Environment (TEE) to help protect users from a
compromised OS and hypervisor. Today TEE can only be leveraged
either by vendor apps or by developers who work with the vendor.
Since vendors consider third-party app code untrusted inside the
TEE, to allow an app to leverage TEE, app developers have to
write the app code in a tailored way to work with the vendor’s
SDK. We proposed a novel design to integrate TEE with mobile
OS to allow any app to leverage the TEE. Our design incorporates
TEE support at the OS level, allowing apps to leverage the TEE
without adding app-specific code into the TEE, and while using
existing interface to interact with the mobile OS. We implemented
our design, called TruZ-Droid, by integrating TrustZone TEE with
the Android OS. TruZ-Droid allows apps to leverage the TEE to
protect the following: (i) user’s secret input and confirmation, and
(ii) sending of user’s secrets to the authorized server. We built a
prototype using the TrustZone-enabled HiKey board to evaluate
our design. We demonstrated TruZ-Droid’s effectiveness by adding
new security features to existing apps to protect user’s sensitive
information and attest user’s confirmation. TruZ-Droid’s real-world
use case evaluation shows that apps can leverage TrustZone while
using existing OS APIs. Our usability study proves that users can
correctly interact with TruZ-Droid to protect their security sensitive
activities and data.
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- Award ID(s):
- 1718086
- NSF-PAR ID:
- 10066262
- Date Published:
- Journal Name:
- The 16th ACM International Conference on Mobile Systems, Applications, and Services (MobiSys 2018)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
