Add instructions on how to run the tests with Nix(OS)

.gitignore

@@ -1,2 +1,5 @@
 __pycache__
 
+build/
+out/
+out.zip

README.md

@@ -33,6 +33,13 @@ $ python run_algtest.py all
 
 **Important:** If during keygen test you don't see lines ending with `rc 0000`, but see some other number (return code), the key generation fails and it doesn't make sense to continue. Please contact me and send me the `out.zip` file anyway, the logs and TPM info there will still help us. A few erroneous return codes are ok.
 
+### Running the tool with Nix(OS)
+
+On NixOS, update your `/etc/nixos/configuration.nix` according to the [TPM instructions](https://nixos.wiki/wiki/TPM) and rebuild your environment. To enter a development shell, use `nix develop`. Then you can build the `tpm2-algtest` using the previously mentioned build instructions. Python's virtual environment is set up automatically, therefore, run the tests after the build with:
+```sh
+$ python run_algtest.py all
+```
+
 ### Troubleshooting
 If the script crashes with this message:
 ```

flake.nix

@@ -0,0 +1,42 @@
+{
+  description = "TPM Algtest";
+
+  inputs = {
+    nixpkgs.url      = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url  = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+        pythonPackages = with pkgs.python311Packages; [
+          venvShellHook
+
+        ];
+      in
+      with pkgs;
+      {
+        devShells.default = mkShell {
+          buildInputs = [
+            python311
+            cmake
+            openssl
+            tpm2-tools
+            tpm2-tss
+          ] ++ pythonPackages;
+
+          venvDir = ".virt";
+          postVenvCreation = ''
+            unset SOURCE_DATE_EPOCH
+            pip install --upgrade pip
+            pip install wheel
+            pip install --requirement requirements.txt
+          '';
+        };
+      }
+    );
+}