Data Loss Prevention and Storage Utilization Improvement of the Hidden Volume on Mobile Devices

Sensitive data protection is vital for mobile users. An effective way is to store sensitive data in the hidden volume of mobile devices with Plausibly Deniable Encryption (PDE) systems. Typically, PDE creates a hidden volume inside the outer volume. However, existing PDE systems could lose data, due to overriding the hidden volume, and significantly waste physical storage, because of the fixedly reserved area for the hidden volume. In this paper, we present MobiGyges to solve the above problems. MobiGyges leverages the Thin Pool to coordinate the storage allocation for both the outer volume and the hidden volume which avoids data override and prevents data loss. Moreover, it improves the storage efficiency by virtualizing the total physical storage into small storage blocks and utilizing the blocks for the outer volume and the hidden volume, which eliminates the reserved area. We implement MobiGyges prototype on Google Nexus 6P with LineageOS 13 operating system. Experimental results show that MobiGyges avoids data loss and improves storage utilization up to 31% compared with existing works.