App backup deduplication research

[grote]

Currently, Seedvault stores all app data as it receives it by the system: one large block per app. Seedvault's storage encryption was developed in collaboration with the developers of well known backup tools as well as security researchers. It uses clever tricks to deduplicate data and allow restore of several backup snapshots while only storing the data once. In this ticket, we want to research how a similar concept could be applied to app backups as well.

• [ ] Research options for deduplicating app data and allowing different snapshots and faster integrity verification
• [ ] Write up finding in a research report and publish this in the project repository