Merge branch 'hans/ssh/ecdsa/OTP-12936' into maint

6 files changed, 174 insertions, 83 deletions

diff --git a/lib/ssh/src/ssh_auth.erl b/lib/ssh/src/ssh_auth.erl
index 726f52132f..0c16e19701 100644
--- a/lib/ssh/src/ssh_auth.erl
+++ b/lib/ssh/src/ssh_auth.erl
@@ -31,8 +31,7 @@
 -export([publickey_msg/1, password_msg/1, keyboard_interactive_msg/1,
 	 service_request_msg/1, init_userauth_request_msg/1,
 	 userauth_request_msg/1, handle_userauth_request/3,
-	 handle_userauth_info_request/3, handle_userauth_info_response/2,
-	 default_public_key_algorithms/0
+	 handle_userauth_info_request/3, handle_userauth_info_response/2
 	]).
 
 %%--------------------------------------------------------------------
@@ -42,27 +41,29 @@ publickey_msg([Alg, #ssh{user = User,
 		       session_id = SessionId,
 		       service = Service,
 		       opts = Opts} = Ssh]) ->
-
     Hash = sha, %% Maybe option?!
     KeyCb = proplists:get_value(key_cb, Opts, ssh_file),
-
     case KeyCb:user_key(Alg, Opts) of
 	{ok, Key} ->
 	    StrAlgo = algorithm_string(Alg),
-	    PubKeyBlob = encode_public_key(Key),
-	    SigData = build_sig_data(SessionId, 
-				     User, Service, PubKeyBlob, StrAlgo),
-	    Sig = ssh_transport:sign(SigData, Hash, Key),
-	    SigBlob = list_to_binary([?string(StrAlgo), ?binary(Sig)]),
-	    ssh_transport:ssh_packet(
-	      #ssh_msg_userauth_request{user = User,
-					service = Service,
-					method = "publickey",
-					data = [?TRUE,
-						?string(StrAlgo),
-						?binary(PubKeyBlob),
-						?binary(SigBlob)]},
-	      Ssh);
+            case encode_public_key(StrAlgo, Key) of
+		not_ok ->
+		    not_ok;
+		PubKeyBlob ->
+		    SigData = build_sig_data(SessionId, 
+					     User, Service, PubKeyBlob, StrAlgo),
+		    Sig = ssh_transport:sign(SigData, Hash, Key),
+		    SigBlob = list_to_binary([?string(StrAlgo), ?binary(Sig)]),
+		    ssh_transport:ssh_packet(
+		      #ssh_msg_userauth_request{user = User,
+						service = Service,
+						method = "publickey",
+						data = [?TRUE,
+							?string(StrAlgo),
+							?binary(PubKeyBlob),
+							?binary(SigBlob)]},
+		      Ssh)
+	    end;
      	_Error ->
 	    not_ok
     end.
@@ -121,7 +122,7 @@ init_userauth_request_msg(#ssh{opts = Opts} = Ssh) ->
 
 	    Algs = proplists:get_value(public_key, 
 				       proplists:get_value(preferred_algorithms, Opts, []),
-				       default_public_key_algorithms()),
+				       ssh_transport:default_algorithms(public_key)),
 	    Prefs = method_preference(Algs),
 	    ssh_transport:ssh_packet(Msg, Ssh#ssh{user = User,
 						  userauth_preference = Prefs,
@@ -355,8 +356,6 @@ handle_userauth_info_response(#ssh_msg_userauth_info_response{},
 			      language = "en"}).
 
 
-default_public_key_algorithms() -> ?PREFERRED_PK_ALGS.
-
 %%--------------------------------------------------------------------
 %%% Internal functions
 %%--------------------------------------------------------------------
@@ -431,10 +430,13 @@ build_sig_data(SessionId, User, Service, KeyBlob, Alg) ->
 	   ?binary(KeyBlob)],
     list_to_binary(Sig).
 
-algorithm_string('ssh-rsa') ->
-    "ssh-rsa";
-algorithm_string('ssh-dss') ->
-    "ssh-dss".
+algorithm_string('ssh-rsa') -> "ssh-rsa";
+algorithm_string('ssh-dss') -> "ssh-dss";
+algorithm_string('ecdsa-sha2-nistp256') -> "ecdsa-sha2-nistp256";
+algorithm_string('ecdsa-sha2-nistp384') -> "ecdsa-sha2-nistp384";
+algorithm_string('ecdsa-sha2-nistp521') -> "ecdsa-sha2-nistp521".
+
+
 
 decode_keyboard_interactive_prompts(_NumPrompts, Data) ->
     ssh_message:decode_keyboard_interactive_prompts(Data, []).
@@ -497,11 +499,35 @@ decode_public_key_v2(<<?UINT32(Len0), _:Len0/binary,
 		       ?UINT32(Len4), Y:Len4/big-signed-integer-unit:8>>
 			 , "ssh-dss") ->
     {ok, {Y, #'Dss-Parms'{p = P, q = Q, g = G}}};
-
+decode_public_key_v2(<<?UINT32(Len0), _:Len0/binary,
+		       ?UINT32(Len1), Id:Len1/binary, %% Id = <<"nistp256">> for example
+		       ?UINT32(Len2), Blob:Len2/binary>>,
+		     Curve) -> 
+    Id = 
+	case Curve of
+	    "ecdsa-sha2-nistp256" -> <<"nistp256">>;
+	    "ecdsa-sha2-nistp384" -> <<"nistp384">>;
+	    "ecdsa-sha2-nistp521" -> <<"nistp521">>
+	end,
+    {ok, {#'ECPoint'{point=Blob}, Id}};
 decode_public_key_v2(_, _) ->
     {error, bad_format}.
 
-encode_public_key(#'RSAPrivateKey'{publicExponent = E, modulus = N}) ->
+encode_public_key("ssh-rsa", #'RSAPrivateKey'{publicExponent = E, modulus = N}) ->
     ssh_bits:encode(["ssh-rsa",E,N], [string,mpint,mpint]);
-encode_public_key(#'DSAPrivateKey'{p = P, q = Q, g = G, y = Y}) ->
-    ssh_bits:encode(["ssh-dss",P,Q,G,Y], [string,mpint,mpint,mpint,mpint]).
+encode_public_key("ssh-dss", #'DSAPrivateKey'{p = P, q = Q, g = G, y = Y}) ->
+    ssh_bits:encode(["ssh-dss",P,Q,G,Y], [string,mpint,mpint,mpint,mpint]);
+encode_public_key("ecdsa-sha2-"++Curve, #'ECPrivateKey'{parameters = Params,
+							publicKey = Pub}) ->
+    Id = ecdsa_id(Params),
+    if
+	Id =/= Curve ->
+	    not_ok;
+	true ->
+	    ssh_bits:encode(["ecdsa-sha2-"++Id, Id, Pub],
+			    [string, string, binary])
+    end.
+
+ecdsa_id({namedCurve,?'secp256r1'}) -> "nistp256";
+ecdsa_id({namedCurve,?'secp384r1'}) -> "nistp384";
+ecdsa_id({namedCurve,?'secp521r1'}) -> "nistp521".
diff --git a/lib/ssh/src/ssh_auth.hrl b/lib/ssh/src/ssh_auth.hrl
index 71f222f6d7..5197a42fa4 100644
--- a/lib/ssh/src/ssh_auth.hrl
+++ b/lib/ssh/src/ssh_auth.hrl
@@ -24,8 +24,6 @@
 
 -define(SUPPORTED_AUTH_METHODS, "publickey,keyboard-interactive,password").
 
--define(PREFERRED_PK_ALGS, ['ssh-rsa','ssh-dss']).
-
 -define(SSH_MSG_USERAUTH_REQUEST,  50).
 -define(SSH_MSG_USERAUTH_FAILURE,  51).
 -define(SSH_MSG_USERAUTH_SUCCESS,  52).
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index ee1dd5c9ce..7fb86c1108 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -1266,9 +1266,9 @@ supported_host_keys(client, _, Options) ->
 				 proplists:get_value(preferred_algorithms,Options,[])
 				) of
 	    undefined -> 
-		ssh_auth:default_public_key_algorithms();
+		ssh_transport:default_algorithms(public_key);
 	    L ->
-		L -- (L--ssh_auth:default_public_key_algorithms())
+		L -- (L--ssh_transport:default_algorithms(public_key))
 	end
     of
 	[] ->
@@ -1280,21 +1280,17 @@ supported_host_keys(client, _, Options) ->
 	    {stop, {shutdown, Reason}}
     end;
 supported_host_keys(server, KeyCb, Options) ->
-    Algs=
     [atom_to_list(A) || A <- proplists:get_value(public_key, 
 						 proplists:get_value(preferred_algorithms,Options,[]),
-						 ssh_auth:default_public_key_algorithms()
+						 ssh_transport:default_algorithms(public_key)
 						),
 			available_host_key(KeyCb, A, Options)
-    ],
-    Algs.
-
+    ].
 
 %% Alg :: atom()
 available_host_key(KeyCb, Alg, Opts) ->
     element(1, catch KeyCb:host_key(Alg, Opts)) == ok.
 
-
 send_msg(Msg, #state{socket = Socket, transport_cb = Transport}) ->
     Transport:send(Socket, Msg).
 
diff --git a/lib/ssh/src/ssh_file.erl b/lib/ssh/src/ssh_file.erl
index b98a8a8410..4e6d58cbff 100644
--- a/lib/ssh/src/ssh_file.erl
+++ b/lib/ssh/src/ssh_file.erl
@@ -52,8 +52,20 @@ host_key(Algorithm, Opts) ->
     %% so probably we could hardcod Password = ignore, but
     %% we keep it as an undocumented option for now.
     Password = proplists:get_value(identity_pass_phrase(Algorithm), Opts, ignore),
-    decode(File, Password).
-
+    case decode(File, Password) of
+	{ok,Key} ->
+	    case {Key,Algorithm} of
+		{#'RSAPrivateKey'{}, 'ssh-rsa'} -> {ok,Key};
+		{#'DSAPrivateKey'{}, 'ssh-dss'} -> {ok,Key};
+		{#'ECPrivateKey'{parameters = {namedCurve, ?'secp256r1'}}, 'ecdsa-sha2-nistp256'} -> {ok,Key};
+		{#'ECPrivateKey'{parameters = {namedCurve, ?'secp384r1'}}, 'ecdsa-sha2-nistp384'} -> {ok,Key};
+		{#'ECPrivateKey'{parameters = {namedCurve, ?'secp521r1'}}, 'ecdsa-sha2-nistp521'} -> {ok,Key};
+		_ -> 
+		    {error,bad_keytype_in_file}
+	    end;
+	Other ->
+	    Other
+    end.
 
 is_auth_key(Key, User,Opts) ->
     case lookup_user_key(Key, User, Opts) of
@@ -81,16 +93,15 @@ user_key(Algorithm, Opts) ->
 
 %% Internal functions %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
-file_base_name('ssh-rsa') ->
-    "ssh_host_rsa_key";
-file_base_name('ssh-dss') ->
-    "ssh_host_dsa_key";
-file_base_name(_) ->
-    "ssh_host_key".
+file_base_name('ssh-rsa'            ) -> "ssh_host_rsa_key";
+file_base_name('ssh-dss'            ) -> "ssh_host_dsa_key";
+file_base_name('ecdsa-sha2-nistp256') -> "ssh_host_ecdsa_key";
+file_base_name('ecdsa-sha2-nistp384') -> "ssh_host_ecdsa_key";
+file_base_name('ecdsa-sha2-nistp521') -> "ssh_host_ecdsa_key";
+file_base_name(_                    ) -> "ssh_host_key".
 
 decode(File, Password) ->
-    try 
-	{ok, decode_ssh_file(read_ssh_file(File), Password)}
+    try {ok, decode_ssh_file(read_ssh_file(File), Password)}
     catch 
 	throw:Reason ->
 	    {error, Reason};
@@ -215,20 +226,18 @@ do_lookup_host_key(KeyToMatch, Host, Alg, Opts) ->
 	Error -> Error
     end.
 
-identity_key_filename('ssh-dss') ->
-    "id_dsa";
-identity_key_filename('ssh-rsa') ->
-    "id_rsa".
-
-identity_pass_phrase("ssh-dss") ->
-    dsa_pass_phrase;
-identity_pass_phrase('ssh-dss') ->
-    dsa_pass_phrase;
-identity_pass_phrase('ssh-rsa') ->
-    rsa_pass_phrase;
-identity_pass_phrase("ssh-rsa") ->
-    rsa_pass_phrase.
-
+identity_key_filename('ssh-dss'            ) -> "id_dsa";
+identity_key_filename('ssh-rsa'            ) -> "id_rsa";
+identity_key_filename('ecdsa-sha2-nistp256') -> "id_ecdsa";
+identity_key_filename('ecdsa-sha2-nistp384') -> "id_ecdsa";
+identity_key_filename('ecdsa-sha2-nistp521') -> "id_ecdsa".
+
+identity_pass_phrase("ssh-dss"       ) -> dsa_pass_phrase;
+identity_pass_phrase("ssh-rsa"       ) -> rsa_pass_phrase;
+identity_pass_phrase("ecdsa-sha2-"++_) -> ecdsa_pass_phrase;
+identity_pass_phrase(P) when is_atom(P) -> 
+    identity_pass_phrase(atom_to_list(P)).
+    
 lookup_host_key_fd(Fd, KeyToMatch, Host, KeyType) ->
     case io:get_line(Fd, '') of
 	eof ->
@@ -267,6 +276,12 @@ key_match(#'RSAPublicKey'{}, 'ssh-rsa') ->
     true;
 key_match({_, #'Dss-Parms'{}}, 'ssh-dss') ->
     true;
+key_match({#'ECPoint'{},<<"nistp256">>}, 'ecdsa-sha2-nistp256') ->
+    true;
+key_match({#'ECPoint'{},<<"nistp384">>}, 'ecdsa-sha2-nistp384') ->
+    true;
+key_match({#'ECPoint'{},<<"nistp521">>}, 'ecdsa-sha2-nistp521') ->
+    true;
 key_match(_, _) ->
     false.
 
diff --git a/lib/ssh/src/ssh_message.erl b/lib/ssh/src/ssh_message.erl
index cb1dcb67c5..cfa11903fb 100644
--- a/lib/ssh/src/ssh_message.erl
+++ b/lib/ssh/src/ssh_message.erl
@@ -564,9 +564,11 @@ decode_kex_init(<<?UINT32(Len), Data:Len/binary, Rest/binary>>, Acc, N) ->
 decode_sign(<<?UINT32(Len), _Alg:Len/binary, ?UINT32(_), Signature/binary>>) ->
     Signature.
 
+
 decode_host_key(<<?UINT32(Len), Alg:Len/binary, Rest/binary>>) ->
     decode_host_key(Alg, Rest).
 
+
 decode_host_key(<<"ssh-rsa">>, <<?UINT32(Len0), E:Len0/big-signed-integer-unit:8,
 				 ?UINT32(Len1), N:Len1/big-signed-integer-unit:8>>) ->
     #'RSAPublicKey'{publicExponent = E,
@@ -579,19 +581,43 @@ decode_host_key(<<"ssh-dss">>,
 		  ?UINT32(Len3), Y:Len3/big-signed-integer-unit:8>>) ->
     {Y, #'Dss-Parms'{p = P,
 		     q = Q,
-		     g = G}}.
+		     g = G}};
+
+decode_host_key(<<"ecdsa-sha2-",Id/binary>>,
+		<<?UINT32(Len0), Id:Len0/binary, %% Id = <<"nistp256">> for example
+		  ?UINT32(Len1), Blob:Len1/binary>>) ->
+    {#'ECPoint'{point=Blob}, Id}.
+
 
 encode_host_key(#'RSAPublicKey'{modulus = N, publicExponent = E}) ->
     ssh_bits:encode(["ssh-rsa", E, N], [string, mpint, mpint]);
 encode_host_key({Y,  #'Dss-Parms'{p = P, q = Q, g = G}}) ->
     ssh_bits:encode(["ssh-dss", P, Q, G, Y],
 		    [string, mpint, mpint, mpint, mpint]);
+encode_host_key({#'ECPoint'{point = Q}, Id}) ->
+    ssh_bits:encode([<<"ecdsa-sha2-",Id/binary>>,Id,Q], [binary,binary,binary]);
+
 encode_host_key(#'RSAPrivateKey'{modulus = N, publicExponent = E}) ->
     ssh_bits:encode(["ssh-rsa", E, N], [string, mpint, mpint]);
 encode_host_key(#'DSAPrivateKey'{y = Y, p = P, q = Q, g = G}) ->
     ssh_bits:encode(["ssh-dss", P, Q, G, Y],
-		    [string, mpint, mpint, mpint, mpint]).
+		    [string, mpint, mpint, mpint, mpint]);
+encode_host_key(#'ECPrivateKey'{parameters = Params, %{namedCurve,{1,2,840,10045,3,1,7}},
+				publicKey = Pub}) ->
+    Id = ecdsa_id(Params),
+    ssh_bits:encode(["ecdsa-sha2-"++Id, Id, Pub],
+                    [string, string, binary]).
+
+
 encode_sign(#'RSAPrivateKey'{}, Signature) ->
     ssh_bits:encode(["ssh-rsa", Signature],[string, binary]);
 encode_sign(#'DSAPrivateKey'{}, Signature) ->
-    ssh_bits:encode(["ssh-dss", Signature],[string, binary]).
+    ssh_bits:encode(["ssh-dss", Signature],[string, binary]);
+encode_sign(#'ECPrivateKey'{parameters = Params}, Signature) ->
+    Id = "ecdsa-sha2-" ++ ecdsa_id(Params),
+    ssh_bits:encode([Id, Signature],[string, binary]).
+
+
+ecdsa_id({namedCurve,?'secp256r1'}) -> "nistp256";
+ecdsa_id({namedCurve,?'secp384r1'}) -> "nistp384";
+ecdsa_id({namedCurve,?'secp521r1'}) -> "nistp521".
diff --git a/lib/ssh/src/ssh_transport.erl b/lib/ssh/src/ssh_transport.erl
index 840564e246..8030c1dc25 100644
--- a/lib/ssh/src/ssh_transport.erl
+++ b/lib/ssh/src/ssh_transport.erl
@@ -65,7 +65,8 @@ default_algorithms() -> [{K,default_algorithms(K)} || K <- algo_classes()].
 
 algo_classes() -> [kex, public_key, cipher, mac, compression].
 
-default_algorithms(kex) -> supported_algorithms(kex, []); %% Just to have a call...
+default_algorithms(kex) -> 
+    supported_algorithms(kex, []); %% Just to have a call to supported_algorithms/2
 default_algorithms(Alg) ->
     supported_algorithms(Alg).
 
@@ -84,7 +85,14 @@ supported_algorithms(kex) ->
        {'diffie-hellman-group1-sha1',           [{public_keys,dh},   {hashs,sha}]}
       ]);
 supported_algorithms(public_key) ->
-    ssh_auth:default_public_key_algorithms();
+    select_crypto_supported(
+      [{'ecdsa-sha2-nistp256',  [{public_keys,ecdsa}, {hashs,sha256}, {ec_curve,secp256r1}]},
+       {'ecdsa-sha2-nistp384',  [{public_keys,ecdsa}, {hashs,sha384}, {ec_curve,secp384r1}]},
+       {'ecdsa-sha2-nistp521',  [{public_keys,ecdsa}, {hashs,sha512}, {ec_curve,secp521r1}]},
+       {'ssh-rsa',              [{public_keys,rsa},   {hashs,sha}                         ]},
+       {'ssh-dss',              [{public_keys,dss},   {hashs,sha}                         ]}
+      ]);
+ 
 supported_algorithms(cipher) ->
     same(
       select_crypto_supported(
@@ -640,33 +648,40 @@ get_host_key(SSH) ->
     #ssh{key_cb = Mod, opts = Opts, algorithms = ALG} = SSH,
 
     case Mod:host_key(ALG#alg.hkey, Opts) of
-	{ok, #'RSAPrivateKey'{} = Key} ->
-	    Key;
-	{ok, #'DSAPrivateKey'{} = Key} ->
-	    Key;
+	{ok, #'RSAPrivateKey'{} = Key} ->  Key;
+	{ok, #'DSAPrivateKey'{} = Key} ->  Key;
+	{ok, #'ECPrivateKey'{}  = Key} ->  Key;
 	Result ->
 	    exit({error, {Result, unsupported_key_type}})
     end.
 
-sign_host_key(_Ssh, #'RSAPrivateKey'{} = Private, H) ->
-    Hash = sha,
-    _Signature = sign(H, Hash, Private);
-sign_host_key(_Ssh, #'DSAPrivateKey'{} = Private, H) ->
-    Hash = sha,
-    _RawSignature = sign(H, Hash, Private).
+sign_host_key(_Ssh, PrivateKey, H) ->
+     sign(H, sign_host_key_sha(PrivateKey), PrivateKey).
+
+sign_host_key_sha(#'ECPrivateKey'{parameters = {namedCurve, ?'secp256r1'}}) -> sha256;
+sign_host_key_sha(#'ECPrivateKey'{parameters = {namedCurve, ?'secp384r1'}}) -> sha384;
+sign_host_key_sha(#'ECPrivateKey'{parameters = {namedCurve, ?'secp521r1'}}) -> sha512;
+sign_host_key_sha(#'RSAPrivateKey'{}) -> sha;
+sign_host_key_sha(#'DSAPrivateKey'{}) -> sha.
+
 
 verify_host_key(SSH, PublicKey, Digest, Signature) ->
-    case verify(Digest, sha, Signature, PublicKey) of
+    case verify(Digest, host_key_sha(PublicKey), Signature, PublicKey) of
 	false ->
 	    {error, bad_signature};
 	true ->
 	    known_host_key(SSH, PublicKey, public_algo(PublicKey))
     end.
 
-public_algo(#'RSAPublicKey'{}) ->
-    'ssh-rsa';
-public_algo({_, #'Dss-Parms'{}}) ->
-    'ssh-dss'.
+host_key_sha(#'RSAPublicKey'{}) ->   sha;
+host_key_sha({_, #'Dss-Parms'{}}) -> sha;
+host_key_sha({#'ECPoint'{},Id}) ->   sha(list_to_atom(binary_to_list(Id))).
+
+
+public_algo(#'RSAPublicKey'{}) ->   'ssh-rsa';
+public_algo({_, #'Dss-Parms'{}}) -> 'ssh-dss';
+public_algo({#'ECPoint'{},Id}) -> list_to_atom("ecdsa-sha2-" ++ binary_to_list(Id)).
+
 
 accepted_host(Ssh, PeerName, Opts) ->
     case proplists:get_value(silently_accept_hosts, Opts, false) of
@@ -906,6 +921,10 @@ sign(SigData, Hash,  #'DSAPrivateKey'{} = Key) ->
     DerSignature = public_key:sign(SigData, Hash, Key),
     #'Dss-Sig-Value'{r = R, s = S} = public_key:der_decode('Dss-Sig-Value', DerSignature),
     <<R:160/big-unsigned-integer, S:160/big-unsigned-integer>>;
+sign(SigData, Hash, Key = #'ECPrivateKey'{}) ->
+    DerEncodedSign =  public_key:sign(SigData, Hash, Key),
+    #'ECDSA-Sig-Value'{r=R, s=S} = public_key:der_decode('ECDSA-Sig-Value', DerEncodedSign),
+    ssh_bits:encode([R,S], [mpint,mpint]);
 sign(SigData, Hash, Key) ->
     public_key:sign(SigData, Hash, Key).
 
@@ -913,6 +932,17 @@ verify(PlainText, Hash, Sig, {_,  #'Dss-Parms'{}} = Key) ->
     <<R:160/big-unsigned-integer, S:160/big-unsigned-integer>> = Sig,
     Signature = public_key:der_encode('Dss-Sig-Value', #'Dss-Sig-Value'{r = R, s = S}),
     public_key:verify(PlainText, Hash, Signature, Key);
+verify(PlainText, Hash, Sig, {ECPoint=#'ECPoint'{}, Param}) ->
+    C = case Param of
+	    <<"nistp256">> -> {namedCurve, ?'secp256r1'};
+	    <<"nistp384">> -> {namedCurve, ?'secp384r1'};
+	    <<"nistp521">> -> {namedCurve, ?'secp521r1'}
+	end,
+    <<?UINT32(Rlen),R:Rlen/big-signed-integer-unit:8,
+      ?UINT32(Slen),S:Slen/big-signed-integer-unit:8>> = Sig,
+    Sval = #'ECDSA-Sig-Value'{r=R, s=S},
+    DerEncodedSig = public_key:der_encode('ECDSA-Sig-Value',Sval),
+    public_key:verify(PlainText, Hash, DerEncodedSig, {ECPoint,C});
 verify(PlainText, Hash, Sig, Key) ->
     public_key:verify(PlainText, Hash, Sig, Key).