From a46497e62e8628a03e2d46a3751aa8baae7ba731 Mon Sep 17 00:00:00 2001
From: swrup <swrup@protonmail.com>
Date: Fri, 17 Oct 2025 16:50:21 +0200
Subject: [PATCH] abstr type for signature

---
 src/json.ml       | 29 ++++++++++++++------------
 src/management.ml |  2 +-
 src/types.ml      | 52 +++++++++++++++++++++++++++++++++++------------
 3 files changed, 56 insertions(+), 27 deletions(-)

diff --git a/src/json.ml b/src/json.ml
index 495bbd89..2a5e54f1 100644
--- a/src/json.ml
+++ b/src/json.ml
@@ -73,30 +73,34 @@ module RelativeTime = struct
     |> Jsont.Object.finish
 end
 
-let amount_jsont =
-  Jsont.of_of_string ~kind:"Amount" Amount.of_string ~enc:Amount.to_string
+module Amount = struct
+  open Amount
+
+  let jsont = Jsont.of_of_string ~kind:"Amount" of_string ~enc:to_string
+end
 
 module EddsaPublicKey = struct
   open EddsaPublicKey
 
-  (* todo?: rewrite with of_of_string *)
-  let jsont =
-    let dec = Jsont.Base.dec_result of_string in
-    let enc = Jsont.Base.enc to_string in
-    Jsont.Base.string (Jsont.Base.map ~kind:"EddsaPublicKey" ~dec ~enc ())
+  let jsont = Jsont.of_of_string ~kind:"EddsaPublicKey" of_string ~enc:to_string
 end
 
 module EddsaSignature = struct
-  let jsont = Jsont.string
+  open EddsaSignature
+
+  let jsont = Jsont.of_of_string ~kind:"EddsaSignature" of_b32 ~enc:to_b32
 end
 
 module RsaPublicKey = struct
   open RsaPublicKey
 
-  let jsont =
-    let dec = Jsont.Base.dec_result of_string in
-    let enc = Jsont.Base.enc to_string in
-    Jsont.Base.string (Jsont.Base.map ~kind:"RsaPublicKey" ~dec ~enc ())
+  let jsont = Jsont.of_of_string ~kind:"RsaPublicKey" of_b32 ~enc:to_b32
+end
+
+module RsaSignature = struct
+  open RsaSignature
+
+  let jsont = Jsont.of_of_string ~kind:"RsaSignature" of_b32 ~enc:to_b32
 end
 
 module RsaDenominationKey = struct
@@ -149,7 +153,6 @@ module FutureSignKey = struct
   open FutureSignKey
 
   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
diff --git a/src/management.ml b/src/management.ml
index d0afe432..10d2f327 100644
--- a/src/management.ml
+++ b/src/management.ml
@@ -32,7 +32,7 @@ let mk_future_denom denom_secmod_sign_f
     let open Binary_formats in
     let h_denom_pub =
       (* TODO hash *)
-      let v = pub |> Types.RsaPublicKey.to_string in
+      let v = pub |> Types.RsaPublicKey.to_b32 in
       DenominationHash.{ v= { v } }
     in
     let h_section_name =
diff --git a/src/types.ml b/src/types.ml
index e80498e6..9c444ecf 100644
--- a/src/types.ml
+++ b/src/types.ml
@@ -73,22 +73,24 @@ module EddsaPublicKey = struct
   type t = Mirage_crypto_ec.Ed25519.pub
 
   let of_string s =
+    let open Syntax in
     let open Mirage_crypto_ec in
-    match B32.decode s with
-    | Error _ as err -> err
-    | Ok octets -> (
-        match Ed25519.pub_of_octets octets with
-        | Error e -> Fmt.error "%a" pp_error e
-        | Ok pub -> Ok pub)
+    let* octets = B32.decode s in
+    match Ed25519.pub_of_octets octets with
+    | Error e -> Fmt.error "%a" pp_error e
+    | Ok pub -> Ok pub
 
   let to_string pub =
     pub |> Mirage_crypto_ec.Ed25519.pub_to_octets |> B32.encode
 end
 
-(* TODO sig type
-   abstract type
-   same for RsaSignature *)
-module EddsaSignature = struct
+module EddsaSignature : sig
+  type t
+
+  val sign : key:Mirage_crypto_ec.Ed25519.priv -> string -> t
+  val of_b32 : string -> (t, string) result
+  val to_b32 : t -> string
+end = struct
   (* EdDSA signatures are transmitted as 64-bytes base32
      binary-encoded objects with just the R and S values (base32_ binary-only).
 
@@ -101,20 +103,26 @@ module EddsaSignature = struct
   let sign ~key s =
     (* mirage_crypto: "The result is the concatenation of r and s, as specified in RFC 8032." *)
     Mirage_crypto_ec.Ed25519.sign ~key s
+
+  let of_b32 s = B32.decode s
+
+  let to_b32 t =
+    let s = B32.encode t in
+    assert (String.length s = 64);
+    s
 end
 
 module RsaPublicKey = struct
-  (* RSA public key converted to Crockford Base32. *)
   type t = Mirage_crypto_pk.Rsa.pub
 
-  let of_string s =
+  let of_b32 s =
     let open Syntax in
     let* s = B32.decode s in
     let* v = Util.bin_of_string Binary_formats.RsaPublicKey.bin s in
     let+ v = Mirage_crypto_pk.Rsa.pub ~n:v.n ~e:v.e |> unwrap_err_msg in
     v
 
-  let to_string ({ n; e } : Mirage_crypto_pk.Rsa.pub) =
+  let to_b32 ({ n; e } : Mirage_crypto_pk.Rsa.pub) =
     let open Binary_formats.RsaPublicKey in
     let header = { n_len= Z.size n; e_len= Z.size e } in
     let v = { header; n; e } in
@@ -123,6 +131,24 @@ module RsaPublicKey = struct
     s
 end
 
+module RsaSignature : sig
+  type t
+
+  val sign : key:Mirage_crypto_pk.Rsa.priv -> string -> t
+  val of_b32 : string -> (t, string) result
+  val to_b32 : t -> string
+end = struct
+  type t = string
+
+  (* no Rsa.sign(?):
+     decrypt is equivalent to sign *)
+  let sign ~key s =
+    Mirage_crypto_pk.Rsa.decrypt ~crt_hardening:true ~mask:`Yes ~key s
+
+  let of_b32 s = B32.decode s
+  let to_b32 t = B32.encode t
+end
+
 module HashCode = struct
   (* 32-byte value representing a point on Curve25519. *)
   type cs25519Point = string