Working with encrypted data requires proper management of cryptographic keys to prevent theft or even loss; here, a loss of the keys amounts to a loss of the encrypted data. For a safe and reliable long-term storage of (small amounts of) critical data such as keys, paper has been an underestimated option - partially due to a lack of good tooling. We therefore have published our own tool Harpocrates as an open-source tool for paper-based backup and recovery.
Manually implementing the generation of HAL resources for REST/HATEOAS-based web services in Java can be tedious. To simplify the implementation, we have published our library Haley under the Apache License 2.0 on Github.