diff --git a/src/dune b/src/dune
index 4c947c3a..0a6fa0ea 100644
--- a/src/dune
+++ b/src/dune
@@ -8,7 +8,6 @@
  (name mte)
  (wrapped false)
  (modules :standard \ mte b32)
- (modules_without_implementation mod_intf)
  (libraries
   b32
   ;
diff --git a/src/keys.ml b/src/keys.ml
index ed1d7635..69721fec 100644
--- a/src/keys.ml
+++ b/src/keys.ml
@@ -4,9 +4,31 @@ open Crypto
 (* TODO better error type *)
 type 'a result = ('a, string) Result.t
 
-module type S = Mod_intf.KEYS
+module type S = sig
+  val sign : eddsa_pub -> string -> eddsa_sig
+  val sign_denom : rsa_pub -> string -> rsa_sig
+  val find_signkey : eddsa_pub -> Signkey.t option result
+  val find_denomination : denom_hash -> Denomination.t option result
+  val signkeys : unit -> Signkey.t list result
+  val denominations : unit -> Denomination.t list result
+  val future_signkeys : unit -> Api.FutureSignKey.t list result
+  val future_denominations : unit -> Api.FutureDenom.t list result
+  val make_future_keys_response : unit -> Api.FutureKeysResponse.t result
 
-module Make (Conn : Pg.CONN) = struct
+  val certify_future_signkey :
+    eddsa_pub -> Signatures.ExchangeSigningKeyValidity.t -> unit result
+
+  val certify_future_denomination :
+    denom_hash -> Signatures.DenominationKeyValidity.t -> unit result
+
+  val revoke_signkey :
+    eddsa_pub -> Signatures.MasterSigningKeyRevocation.t -> unit result
+
+  val revoke_denomination :
+    denom_hash -> Signatures.MasterDenominationKeyRevocation.t -> unit result
+end
+
+module Make (Conn : Pg.CONN) : S = struct
   module Sm_eddsa = Secmod_eddsa.Make ()
   module Sm_rsa = Secmod_rsa.Make ()
 
diff --git a/src/keys.mli b/src/keys.mli
deleted file mode 100644
index abf3e388..00000000
--- a/src/keys.mli
+++ /dev/null
@@ -1,3 +0,0 @@
-module type S = Mod_intf.KEYS
-
-module Make (_ : Pg.CONN) : S
diff --git a/src/mod_intf.mli b/src/mod_intf.mli
deleted file mode 100644
index 1bea500c..00000000
--- a/src/mod_intf.mli
+++ /dev/null
@@ -1,27 +0,0 @@
-open Crypto
-
-type 'a result = ('a, string) Result.t
-
-module type KEYS = sig
-  val sign : eddsa_pub -> string -> eddsa_sig
-  val sign_denom : rsa_pub -> string -> rsa_sig
-  val find_signkey : eddsa_pub -> Signkey.t option result
-  val find_denomination : denom_hash -> Denomination.t option result
-  val signkeys : unit -> Signkey.t list result
-  val denominations : unit -> Denomination.t list result
-  val future_signkeys : unit -> Api.FutureSignKey.t list result
-  val future_denominations : unit -> Api.FutureDenom.t list result
-  val make_future_keys_response : unit -> Api.FutureKeysResponse.t result
-
-  val certify_future_signkey :
-    eddsa_pub -> Signatures.ExchangeSigningKeyValidity.t -> unit result
-
-  val certify_future_denomination :
-    denom_hash -> Signatures.DenominationKeyValidity.t -> unit result
-
-  val revoke_signkey :
-    eddsa_pub -> Signatures.MasterSigningKeyRevocation.t -> unit result
-
-  val revoke_denomination :
-    denom_hash -> Signatures.MasterDenominationKeyRevocation.t -> unit result
-end