44 dkg improvements

dkg/pedersen/dkg.go

@@ -116,6 +116,15 @@ func (s *instance) handleMessage(
 	// receive other messages in the meantime, like a Deal.
 	switch msg := msg.(type) {
 
+	case types.GetPeerPubKey:
+		response := types.NewGetPeerPubKeyResp(suite.Point().Mul(s.privKey, nil))
+		errs := out.Send(response, from)
+		err := <-errs
+		if err != nil {
+			return xerrors.Errorf("got an error while sending the get peer pubkey resp "+
+				"reply: %v", err)
+		}
+
 	case types.Start:
 		go func() {
 			err := s.start(ctx, msg, s.deals, s.responses, from, out)

dkg/pedersen/json/json.go

@@ -21,6 +21,12 @@ type Address []byte
 
 type PublicKey []byte
 
+type GetPeerPubKey struct{}
+
+type GetPeerPubKeyResp struct {
+	PublicKey PublicKey
+}
+
 type Start struct {
 	Threshold  int
 	Addresses  []Address
@@ -121,6 +127,8 @@ type ReencryptReply struct {
 }
 
 type Message struct {
+	GetPeerPubKey            *GetPeerPubKey            `json:",omitempty"`
+	GetPeerPubKeyResp        *GetPeerPubKeyResp        `json:",omitempty"`
 	Start                    *Start                    `json:",omitempty"`
 	StartResharing           *StartResharing           `json:",omitempty"`
 	Deal                     *Deal                     `json:",omitempty"`
@@ -155,6 +163,19 @@ func (f msgFormat) Encode(ctx serde.Context, msg serde.Message) ([]byte, error)
 	var err error
 
 	switch in := msg.(type) {
+	case types.GetPeerPubKey:
+		m = Message{
+			GetPeerPubKey: &GetPeerPubKey{},
+		}
+	case types.GetPeerPubKeyResp:
+		v, err := in.GetPublicKey().MarshalBinary()
+		if err != nil {
+			return nil, xerrors.Errorf("failed to marshal pubkey: %v", err)
+		}
+
+		m = Message{GetPeerPubKeyResp: &GetPeerPubKeyResp{
+			PublicKey: v,
+		}}
 	case types.Start:
 		m, err = encodeStart(in)
 	case types.StartResharing:
@@ -226,6 +247,18 @@ func (f msgFormat) Decode(ctx serde.Context, data []byte) (serde.Message, error)
 	}
 
 	switch {
+	case m.GetPeerPubKey != nil:
+		return types.NewGetPeerPubKey(), nil
+
+	case m.GetPeerPubKeyResp != nil:
+		v := f.suite.Point()
+		err = v.UnmarshalBinary(m.GetPeerPubKeyResp.PublicKey)
+		if err != nil {
+			return nil, xerrors.Errorf("failed to unmarshal pubkey: %v", err)
+		}
+
+		return types.NewGetPeerPubKeyResp(v), nil
+
 	case m.Start != nil:
 		return f.decodeStart(ctx, m.Start)
 

dkg/pedersen/json/json_test.go

@@ -18,6 +18,36 @@ import (
 // suite is the Kyber suite for Pedersen.
 var suite = suites.MustFind("Ed25519")
 
+func TestMessageFormat_PeerPublicKey(t *testing.T) {
+	format := newMsgFormat()
+	ctx := serde.NewContext(fake.ContextEngine{})
+
+	data, err := format.Encode(ctx, types.NewGetPeerPubKey())
+	require.NoError(t, err)
+	require.JSONEq(t, `{"GetPeerPubKey":{}}`, string(data))
+
+	request, err := format.Decode(ctx, data)
+	require.NoError(t, err)
+	require.IsType(t, types.GetPeerPubKey{}, request)
+
+	publicKey := suite.Point().Pick(suite.RandomStream())
+	data, err = format.Encode(ctx, types.NewGetPeerPubKeyResp(publicKey))
+	require.NoError(t, err)
+
+	message, err := format.Decode(ctx, data)
+	require.NoError(t, err)
+	response := message.(types.GetPeerPubKeyResp)
+	require.True(t, publicKey.Equal(response.GetPublicKey()))
+
+	_, err = format.Encode(ctx, types.NewGetPeerPubKeyResp(badPoint{}))
+	require.EqualError(t, err,
+		fake.Err("failed to marshal pubkey"))
+
+	_, err = format.Decode(ctx, []byte(`{"GetPeerPubKeyResp":{"PublicKey":[]}}`))
+	require.EqualError(t, err,
+		"failed to unmarshal pubkey: invalid Ed25519 curve point")
+}
+
 func TestMessageFormat_EncodeStart(t *testing.T) {
 	start := types.NewStart(1, []mino.Address{fake.NewAddress(0)}, []kyber.Point{suite.Point()})