diff --git a/src/secmod.ml b/src/secmod.ml
index 548338b6..79b13fae 100644
--- a/src/secmod.ml
+++ b/src/secmod.ml
@@ -20,6 +20,30 @@ type t = {
     Hashtbl.t;
 }
 
+let sign_with_sm_key t s = EddsaSignature.sign ~key:t.sm_key_priv s
+
+let verify_with_sm_key t s ~msg =
+  match EddsaSignature.verify ~key:t.sm_key_pub s ~msg with
+  | false -> Error "signature verification failure: invalid signature"
+  | true -> Ok ()
+
+let sign_with_signkey t ~pub s =
+  Miou.Mutex.protect t.lock @@ fun () ->
+  match Hashtbl.find_opt t.sk_ht pub with
+  | None -> Error "secmod failure: public key not found."
+  | Some signkey ->
+      let v = EddsaSignature.sign ~key:signkey.priv s in
+      Ok v
+
+let verify_with_signkey t ~pub s ~msg =
+  Miou.Mutex.protect t.lock @@ fun () ->
+  match Hashtbl.find_opt t.sk_ht pub with
+  | None -> Error "secmod failure: public key not found."
+  | Some signkey -> (
+      match EddsaSignature.verify ~key:signkey.pub s ~msg with
+      | false -> Error "signature verification failure: invalid signature"
+      | true -> Ok ())
+
 let get_sm_key_priv t = t.sm_key_priv
 let get_sm_key_pub t = t.sm_key_pub
 
diff --git a/src/secmod.mli b/src/secmod.mli
index ba897b50..2d1b289d 100644
--- a/src/secmod.mli
+++ b/src/secmod.mli
@@ -2,6 +2,15 @@ open Crypto
 
 type t
 
+val sign_with_sm_key : t -> string -> eddsa_sig
+val verify_with_sm_key : t -> eddsa_sig -> msg:string -> (unit, string) result
+
+val sign_with_signkey :
+  t -> pub:eddsa_pub -> string -> (eddsa_sig, string) result
+
+val verify_with_signkey :
+  t -> pub:eddsa_pub -> eddsa_sig -> msg:string -> (unit, string) result
+
 val get_sm_key_priv : t -> eddsa_priv
 val get_sm_key_pub : t -> eddsa_pub
 val get_signkeys : t -> Signkey_data.t list