diff --git a/src/secmod_eddsa.ml b/src/secmod_eddsa.ml
index d0fff792..21564eea 100644
--- a/src/secmod_eddsa.ml
+++ b/src/secmod_eddsa.ml
@@ -92,8 +92,8 @@ let split_in_periodes ~start ~end_ =
   go acc start end_
 
 let gen_additional_keys_until_lookahead ~now l =
-  (* try to _not_ generate keys with validity start in the past
-     (probably not important) *)
+  (* TODO do not exceed lookahead (probably more important...) *)
+  (* try to not generate keys with validity start in the past *)
   let start =
     match List.rev (sort_keys l) with
     | [] -> now