nixos-config/nixos/system/desktop/cachix/all-hies.nix

{
  nix.settings = {
    substituters = [ "https://all-hies.cachix.org" ];
    trusted-public-keys = [ "all-hies.cachix.org-1:JjrzAOEUsD9ZMt8fdFbzo3jNAyEWlPAwdVuHw4RD43k=" ];
  };
}