offline tool: verify signature

src/api_sig.ml

@@ -44,7 +44,9 @@ end) : sig
   type t
 
   val sign : key:Crypto.EddsaPrivateKey.t -> r -> t
-  val verify : key:Crypto.EddsaPublicKey.t -> t -> r -> bool
+
+  (* Ok () on verification success *)
+  val verify : key:Crypto.EddsaPublicKey.t -> t -> r -> (unit, string) result
   val jsont : t Jsont.t
 end = struct
   open Crypto
@@ -54,7 +56,13 @@ end = struct
 
   let bin = R.bin
   let sign ~key r = EddsaSignature.sign ~key (Bin.to_string bin r)
-  let verify ~key t r = EddsaSignature.verify ~key t ~msg:(Bin.to_string bin r)
+
+  let verify ~key t r =
+    let b = EddsaSignature.verify ~key t ~msg:(Bin.to_string bin r) in
+    match b with
+    | false -> Error "signature verification failure"
+    | true -> Ok ()
+
   let jsont = EddsaSignature.jsont
 end
 

src/management.ml

@@ -1,7 +1,7 @@
 open Api
 open Devices
 
-let mk_future_denom ~key
+let mk_future_denom ~sm_denom_priv
     ({
        pub;
        priv= _;
@@ -31,7 +31,8 @@ let mk_future_denom ~key
     let duration_withdraw =
       Timestamp.diff stamp_start stamp_expire_withdraw |> Timestamp.of_span_exn
     in
-    sign ~key { h_denom_pub; h_section_name; anchor_time; duration_withdraw }
+    sign ~key:sm_denom_priv
+      { h_denom_pub; h_section_name; anchor_time; duration_withdraw }
   in
   FutureDenom.
     {
@@ -49,7 +50,7 @@ let mk_future_denom ~key
       denom_secmod_sig;
     }
 
-let mk_future_signkey ~key
+let mk_future_signkey ~sm_signkey_priv
     ({ pub; priv= _; stamp_start; stamp_expire; stamp_end; master_sig= _ } :
       Signkey.t) =
   let signkey_secmod_sig =
@@ -59,7 +60,7 @@ let mk_future_signkey ~key
     let duration =
       Timestamp.diff stamp_start stamp_expire |> Timestamp.of_span_exn
     in
-    sign ~key { exchange_pub; anchor_time; duration }
+    sign ~key:sm_signkey_priv { exchange_pub; anchor_time; duration }
   in
   FutureSignKey.
     { key= pub; stamp_start; stamp_expire; stamp_end; signkey_secmod_sig }
@@ -70,15 +71,14 @@ let mk_future_keys_response (secmod_signkey : Secmod_signkey.t)
     secmod_denom.keys
     |> List.filter (fun k -> Option.is_none k.Denomination.master_sig)
     |> List.map (fun denom ->
-        let key = secmod_denom.sm_key.Signkey.priv in
-        mk_future_denom ~key denom)
+        mk_future_denom ~sm_denom_priv:secmod_denom.sm_key.Signkey.priv denom)
   in
   let future_signkeys =
     secmod_signkey.keys
     |> List.filter (fun k -> Option.is_none k.Signkey.master_sig)
     |> List.map (fun signkey ->
-        let key = secmod_denom.sm_key.Signkey.priv in
-        mk_future_signkey ~key signkey)
+        mk_future_signkey ~sm_signkey_priv:secmod_signkey.sm_key.Signkey.priv
+          signkey)
   in
   let master_pub = Config.Exchange.master_public_key in
   let denom_secmod_public_key = secmod_denom.sm_key.pub in

tools/offline_impl.ml

@@ -45,10 +45,13 @@ let sign ~master_key ~input ~output =
   let* input = read_file input in
   let* master_key = read_file master_key in
   let master_key = EddsaPrivateKey.of_octets master_key in
-  let* future_key_response = Api.decode Api.FutureKeysResponse.jsont input in
-  let* () = Offline_sig.verify_future_key_response future_key_response in
+  let master_pub = EddsaPrivateKey.pub_of_priv master_key in
+  let* future_keys_response = Api.decode Api.FutureKeysResponse.jsont input in
+  let* () =
+    Offline_sig.verify_future_keys_response master_pub future_keys_response
+  in
   let master_signatures =
-    Offline_sig.make_master_signatures ~master_key future_key_response
+    Offline_sig.make_master_signatures ~master_key future_keys_response
   in
   let* s = Api.encode Api.MasterSignatures.jsont master_signatures in
   let* () = write_file output s in

tools/offline_sig.ml

@@ -77,6 +77,73 @@ let make_master_signatures ~master_key
   let signkey_sigs = List.map (signkey_signature ~master_key) future_signkeys in
   MasterSignatures.{ denom_sigs; signkey_sigs }
 
-let verify_future_key_response _future_key_response =
-  (* TODO *)
+(* - ** - *)
+
+let verify_future_signkey ~sm_signkey_pub
+    FutureSignKey.
+      { key; stamp_start; stamp_expire; stamp_end= _; signkey_secmod_sig } =
+  let exchange_pub = key in
+  let anchor_time = stamp_start in
+  let duration =
+    Timestamp.diff stamp_start stamp_expire |> Timestamp.of_span_exn
+  in
+  let open Api_sig.SigningKeyAnnouncementPS in
+  verify ~key:sm_signkey_pub signkey_secmod_sig
+    { exchange_pub; anchor_time; duration }
+
+let verify_future_denom ~sm_denom_pub
+    FutureDenom.
+      {
+        section_name;
+        value= _;
+        stamp_start;
+        stamp_expire_withdraw;
+        stamp_expire_deposit= _;
+        stamp_expire_legal= _;
+        denom_pub;
+        fee_withdraw= _;
+        fee_deposit= _;
+        fee_refresh= _;
+        fee_refund= _;
+        denom_secmod_sig;
+      } =
+  let h_denom_pub =
+    DenominationHash.hash (DenominationKey.to_octets denom_pub)
+  in
+  let h_section_name = Hash_64_cstr.hash section_name in
+  let anchor_time = stamp_start in
+  let duration_withdraw =
+    Timestamp.diff stamp_start stamp_expire_withdraw |> Timestamp.of_span_exn
+  in
+  let open Api_sig.DenominationKeyAnnouncementPS in
+  verify ~key:sm_denom_pub denom_secmod_sig
+    { h_denom_pub; h_section_name; anchor_time; duration_withdraw }
+
+let verify_future_keys_response our_master_public_key
+    FutureKeysResponse.
+      {
+        future_denoms;
+        future_signkeys;
+        master_pub;
+        denom_secmod_public_key;
+        signkey_secmod_public_key;
+      } =
+  let open Syntax in
+  let* () =
+    match master_pub = our_master_public_key with
+    | false ->
+        Fmt.error
+          "master public key of the future key response does not match ours"
+    | true -> Ok ()
+  in
+  let* () =
+    list_iter
+      (verify_future_denom ~sm_denom_pub:denom_secmod_public_key)
+      future_denoms
+  in
+  let* () =
+    list_iter
+      (verify_future_signkey ~sm_signkey_pub:signkey_secmod_public_key)
+      future_signkeys
+  in
   Ok ()