Partitioned Private User Storages in End-to-End Encrypted Online Social Networks
This addresses data recovery for users in secure online social networks, though it is incremental as it builds on existing encryption and storage methods.
The paper tackles the problem of permanent data loss in end-to-end encrypted online social networks when users lose login credentials by proposing a scheme to split encrypted user storages into multiple parts that can be reconstructed with help from other participants, achieving high reconstruction success rates even with many inaccessible shares.
In secure Online Social Networks (OSN), often end-to-end encryption approaches are used. This ensures the privacy of communication between the participants. To manage, store, or transfer the cryptographic keys from one device to another one, encrypted private storages can be used. To gain access to such storages, login credentials, only known to the user, are needed. Losing these credentials results in a permanent loss of cryptographic keys and messages because the storage is encrypted. We present a scheme to split encrypted user storages into multiple storages. Each one can be reconstructed with the help of other participants of the OSN. The more of the storages can be reconstructed, the higher the chance of successfully reconstructing the complete private storage is. Therefore, regaining possession of the cryptographic keys used for communication is increased. We achieve high rates of successful reconstructions, even if a large fraction of the distributed shares are not accessible anymore because the shareholders are inactive or malicious.