Added executable, added B64 encoding

Signed-off-by: Louis Hollingworth <louis@hollingworth.nl>

flake.nix

@@ -0,0 +1,32 @@
+{
+  description = "A very basic flake";
+
+  inputs = {
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+    };
+    crane.url = "github:ipetkov/crane";
+    fenix = {
+      url = "github:nix-community/fenix";
+        inputs.nixpkgs.follows = "nixpkgs";
+    };
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  };
+
+  outputs = inputs:
+    with inputs;
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = import nixpkgs {
+          inherit system;
+        };
+        rustPkgs = (crane.mkLib pkgs).overrideToolchain
+          fenix.packages.${system}.beta.toolchain;
+      in {
+        packages = {
+          default = rustPkgs.buildPackage {
+            src = rustPkgs.cleanCargoSource ./.;
+          };
+        };
+      });
+}