diff --git a/src/utils/hash.ml b/src/utils/hash.ml
index b088cfdf3..1e2bc1fce 100644
--- a/src/utils/hash.ml
+++ b/src/utils/hash.ml
@@ -254,7 +254,7 @@ module Hash_map (Hash : HASH) = struct
       Data_encoding.(list (tup2 Hash.encoding arg_encoding))
 end
 
-module Hash_table (Hash : HASH)
+module Hash_table (Hash : MINIMAL_HASH)
   : Hashtbl.S with type key = Hash.t
   = Hashtbl.Make (struct
     type t = Hash.t
diff --git a/src/utils/hash.mli b/src/utils/hash.mli
index 57f8d25b1..aab5d7301 100644
--- a/src/utils/hash.mli
+++ b/src/utils/hash.mli
@@ -103,7 +103,7 @@ module Hash_map (Hash : HASH) : sig
 end
 
 (** Builds a Hashtbl using some Hash type as keys. *)
-module Hash_table (Hash : HASH) : Hashtbl.S with type key = Hash.t
+module Hash_table (Hash : MINIMAL_HASH) : Hashtbl.S with type key = Hash.t
 
 (** {2 Predefined Hashes } ****************************************************)