From 46caf0b57846190f2823e633233f23d23ed3c65c Mon Sep 17 00:00:00 2001
From: swrup <swrup@protonmail.com>
Date: Mon, 6 Oct 2025 22:20:09 +0200
Subject: [PATCH] + Future_sign_key

---
 src/json.ml  | 25 +++++++++++++++++++++++++
 src/types.ml |  4 +++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/json.ml b/src/json.ml
index 219329e4..c4a34de6 100644
--- a/src/json.ml
+++ b/src/json.ml
@@ -83,6 +83,8 @@ module Eddsa = struct
     let dec = Jsont.Base.dec_result pub_of_string in
     let enc = Jsont.Base.enc pub_to_string in
     Jsont.Base.string (Jsont.Base.map ~kind:"EddsaPublicKey" ~dec ~enc ())
+
+  let signature_jsont = Jsont.string
 end
 
 module Rsa_denomination_key = struct
@@ -130,3 +132,26 @@ module Denomination_key = struct
     |> case_mem "cipher" Jsont.string ~enc:Fun.id ~enc_case cases
     |> finish
 end
+
+module Future_sign_key = struct
+  open Future_sign_key
+
+  let jsont =
+    (* TODO ppx? *)
+    let make key stamp_start stamp_expire stamp_end signkey_secmod_sig =
+      { key; stamp_start; stamp_expire; stamp_end; signkey_secmod_sig }
+    in
+    let key v = v.key in
+    let stamp_start v = v.stamp_start in
+    let stamp_expire v = v.stamp_expire in
+    let stamp_end v = v.stamp_end in
+    let signkey_secmod_sig v = v.signkey_secmod_sig in
+    let open Jsont.Object in
+    map ~kind:"FutureSignKey" make
+    |> mem "key" Eddsa.pub_jsont ~enc:key
+    |> mem "stamp_start" Timestamp.jsont ~enc:stamp_start
+    |> mem "stamp_expire" Timestamp.jsont ~enc:stamp_expire
+    |> mem "stamp_end" Timestamp.jsont ~enc:stamp_end
+    |> mem "signkey_secmod_sig" Eddsa.signature_jsont ~enc:signkey_secmod_sig
+    |> finish
+end
diff --git a/src/types.ml b/src/types.ml
index 4eb0d672..f4546537 100644
--- a/src/types.ml
+++ b/src/types.ml
@@ -131,7 +131,9 @@ module Eddsa = struct
     pub |> Mirage_crypto_ec.Ed25519.pub_to_octets |> Base_32.encode
 
   (* EdDSA signatures are transmitted as 64-bytes base32
-   binary-encoded objects with just the R and S values (base32_ binary-only). *)
+     binary-encoded objects with just the R and S values (base32_ binary-only).
+
+     They are signature over a c-struct like `TALER_xxxPS` + with a purpose *)
   type signature = string
 end