Realizing Software Vault on Android Through Information-Flow Control

Several approaches to protect data and code, and ensure execution in a secure environment without getting infected from malwares, such as isolation, sandboxing, trust-based execution, application oriented access control have been proposed. In recent times, hardware-based solutions like ARM TrustZone and Intel SGX Enclave have been introduced to protect code and data from being infected or modified from outside the designated "secure" zone. While the hardware-based approaches have a distinct advantage, they have disadvantages in realizing Multi-Level Secure (MLS) systems, as they need to communicate via a central agent; further, a software vault would provide a good alternative when a system (like smartphone) is used/owned by a single person. In this paper, we describe a general approach for the creation of a software vault to preserve integrity and confidentiality of the information and computation end-to-end while supporting inter-communication among different components. This realizes an efficient interacting system that is secure and as good as the system using the hardware-based solutions. Our solution is through dynamic labelling using the recent information flow models for decentralized systems. We illustrate the application of our technique for building a runtime monitor for the Android environment, and demonstrate its characteristic properties by realizing a secure banking application. The solution guarantees end-to-end preservation of confidentiality & integrity, and allowing interactions among distributed components but still preserving the hardness of penetration from malware. We believe that our software vault will have extensive applications in utility computing that demands inter-communication between clouds.