https://nixos.wiki/wiki/Comparison_of_secret_managing_schemes

2023
https://lgug2z.com/articles/providing-runtime-secrets-to-nixos-services/
2021
https://christine.website/blog/nixos-encrypted-secrets-2021-01-20
2020
https://elvishjerricco.github.io/2018/06/24/secure-declarative-key-management.html