diff --git a/tools/dune b/tools/dune
index 4f5057ca..80d17dd6 100644
--- a/tools/dune
+++ b/tools/dune
@@ -5,7 +5,7 @@
  (libraries cmdliner bos fmt mirage-crypto ptime mte vif))
 
 (executable
- (public_name gen_signatures_registry)
- (name gen_signatures_registry)
- (modules gen_signatures_registry)
+ (public_name gen_taler_signatures)
+ (name gen_taler_signatures)
+ (modules gen_taler_signatures)
  (libraries angstrom bos fmt))
diff --git a/tools/gen_signatures_registry.ml b/tools/gen_taler_signatures.ml
similarity index 85%
rename from tools/gen_signatures_registry.ml
rename to tools/gen_taler_signatures.ml
index dc6a8ede..732bacbd 100644
--- a/tools/gen_signatures_registry.ml
+++ b/tools/gen_taler_signatures.ml
@@ -51,12 +51,7 @@ module Recfile = struct
   let parse s = parse_string ~consume:All recfile s
 end
 
-let url =
-  "https://git-www.gnunet.org/gana.git/plain/gnunet-signatures/registry.rec"
-
-let registry_file = "registry.rec"
-
-let download () =
+let download ~output ~url =
   let open Bos in
   let res =
     OS.Cmd.run
@@ -65,7 +60,7 @@ let download () =
         % "--silent"
         % "--show-error"
         % "-o"
-        % registry_file
+        % output
         % "-X"
         % "GET"
         % url)
@@ -100,19 +95,30 @@ let parse_purposes records =
       | _ -> None)
   |> List.filter (fun v -> v.number >= 1000_l)
 
-let () =
-  download ();
+let print_module purposes =
+  let header =
+    {|(* This file was generated from the GANA database:
+   https://git-www.gnunet.org/gana.git/tree/gnunet-signatures/registry.rec *)|}
+  in
+  let pp ppf { number; name; comment } =
+    Fmt.pf ppf "(** %s *)\nlet %s : int32 = %ld_l\n\n" comment name number
+  in
+  Fmt.pr "%s\n\n%a@." header (Fmt.list ~sep:Fmt.nop pp) purposes;
+  ()
+
+let url =
+  "https://git-www.gnunet.org/gana.git/plain/gnunet-signatures/registry.rec"
+
+(* tmp file *)
+let registry_file = "registry.rec"
+
+let main () =
+  download ~output:registry_file ~url;
   let content = read_file registry_file in
   match Recfile.parse content with
   | Error msg -> Fmt.failwith "Recfile parse error: %s" msg
   | Ok records ->
-      let purposes = parse_purposes records in
-      let header =
-        {|(* This file was generated from the GANA database:
-   https://git-www.gnunet.org/gana.git/tree/gnunet-signatures/registry.rec *)|}
-      in
-      let pp ppf { number; name; comment } =
-        Fmt.pf ppf "(** %s *)\nlet %s : int32 = %ld_l\n\n" comment name number
-      in
-      Fmt.pr "%s\n\n%a@." header (Fmt.list ~sep:Fmt.nop pp) purposes;
+      print_module (parse_purposes records);
       ()
+
+let () = main ()