Mobile devices, such as smart phones and tablets, nowadays have lot of resources that are not always fully leveraged. This project demonstrates how to take advantage of free storage capacity of mobile devices for realizing a distributed backup system. More specifically, the goal is to design and implement a decentralized storage scheme on top of mobile devices, which can be used to backup photos (and potentially other data) on a group of peer devices in a reliable and secure manner. Required features of the system include:

• a mobile app would monitor photo albums (and perhaps other selected folders) on the mobile device, detect file system changes, and then distribute new or modified files among trusted peer devices for later retrieval;
• data stored on peer devices should remain unreadable to the users of those devices, so before distribution, files should be encrypted, such that only their owner can decrypt them;
• data should be stored in a reliable manner, meaning that even if some peers were unavailable, the owner should be able to retrieve their files, so before distribution, encrypted files should be transformed into shards using replication or erasure coding and the shards should be sent to different peers;
• users should be able to form backup groups from trusted peer devices and add multiple devices to their account such that these devices can be part of backup groups;
• data stored at peers should be recoverable by the owner even if they lost all their devices;
• communications between devices should be peer-to-peer, end-to-end encrypted, and authenticated.

The tasks of the student include: 

• refining the set of requirements, 
• designing and implementing the system, 
• documenting the development, and
• demonstrating the operation of the system and its features.