diff --git a/pkgs/tools/graphics/blockhash/default.nix b/pkgs/tools/graphics/blockhash/default.nix
index a0ecdde3826c..b3426722f79f 100644
--- a/pkgs/tools/graphics/blockhash/default.nix
+++ b/pkgs/tools/graphics/blockhash/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitHub, python, pkg-config, imagemagick, wafHook }:
+{ lib, stdenv, fetchFromGitHub, python2, pkg-config, imagemagick, wafHook }:
 
 stdenv.mkDerivation rec {
   pname = "blockhash";
@@ -11,9 +11,11 @@ stdenv.mkDerivation rec {
     sha256 = "0m7ikppl42iicgmwsb7baajmag7v0p1ab06xckifvrr0zm21bq9p";
   };
 
-  nativeBuildInputs = [ python pkg-config wafHook ];
+  nativeBuildInputs = [ python2 pkg-config wafHook ];
   buildInputs = [ imagemagick ];
 
+  strictDeps = true;
+
   meta = with lib; {
     homepage = "http://blockhash.io/";
     description = ''