diff --git a/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml b/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml
index fd599b4fb..debbd574a 100644
--- a/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml
+++ b/src/proto_alpha/lib_protocol/src/blinded_public_key_hash.ml
@@ -7,13 +7,15 @@
 (*                                                                        *)
 (**************************************************************************)
 
-include Blake2B.Make(Base58)(struct
+module H = Blake2B.Make(Base58)(struct
     let name = "Blinded public key hash"
     let title = "A blinded public key hash"
     let b58check_prefix = "\001\002\049\223"
     let size = Some Ed25519.Public_key_hash.size
   end)
 
+include H
+
 let () =
   Base58.check_encoded_prefix b58check_encoding "btz1" 37
 
@@ -30,25 +32,4 @@ let activation_code_of_hex h =
     invalid_arg "Blinded_public_key_hash.activation_code_of_hex" ;
   MBytes.of_hex (`Hex h)
 
-module Index = struct
-
-  type nonrec t = t
-  let path_length = 2
-
-  let rpc_arg = rpc_arg
-  let compare = compare
-  let encoding = encoding
-
-  let to_path bpkh l =
-    let `Hex h =  MBytes.to_hex (to_bytes bpkh) in
-    String.sub h 0 2 :: String.sub h 2 (size - 2) :: l
-
-  let of_path = function
-    | [ h1 ; h2 ] -> of_bytes_opt (MBytes.of_hex (`Hex (h1 ^ h2)))
-    | _ -> None
-
-  let compare = compare
-  let encoding = encoding
-  let rpc_arg = rpc_arg
-
-end
+module Index = H