Dark Crystal is a protocol for distributed data persistence and threshold-based consensus.

Dark Crystal is a protocol for distributed data persistence and threshold-based consensus, and has multiple possible applications in security-oriented tools.

Many tools and applications exist which cater to the security needs of users in high-risk environments. However, difficulties with key management often pose a barrier to their adoption.  In particular, fear of losing access to critical data is a commonly cited deterrent.

Dark Crystal will provide a toolkit for developers of applications where effective management of sensitive data is critical. This will include a protocol for distributed backup and recovery of cryptographic keys, an implementation in Java, and a comprehensive guide to the techniques, including threat modelling and an exploration of the social and technical factors which need consideration.  We will also design, implement and test two features for Briar, a privacy-focussed mobile messaging app, which will demonstrate the utility of the protocol and developer guides.