bring back plaintext 2.0.0 with new constructor (#42)

* bring back plaintext 2.0.0 with new constructor

* fix deprecation comment

* rm unused context argument

* only check remote id validity if we actually have keys

* bring back msgio & simultaneous read/write

crypto/key.go

@@ -279,6 +279,12 @@ func UnmarshalPublicKey(data []byte) (PubKey, error) {
 		return nil, err
 	}
 
+	return PublicKeyFromProto(pmes)
+}
+
+// PublicKeyFromProto converts an unserialized protobuf PublicKey message
+// into its representative object.
+func PublicKeyFromProto(pmes *pb.PublicKey) (PubKey, error) {
 	um, ok := PubKeyUnmarshallers[pmes.GetType()]
 	if !ok {
 		return nil, ErrBadKeyType
@@ -290,6 +296,17 @@ func UnmarshalPublicKey(data []byte) (PubKey, error) {
 // MarshalPublicKey converts a public key object into a protobuf serialized
 // public key
 func MarshalPublicKey(k PubKey) ([]byte, error) {
+	pbmes, err := PublicKeyToProto(k)
+	if err != nil {
+		return nil, err
+	}
+
+	return proto.Marshal(pbmes)
+}
+
+// PublicKeyToProto converts a public key object into an unserialized
+// protobuf PublicKey message.
+func PublicKeyToProto(k PubKey) (*pb.PublicKey, error) {
 	pbmes := new(pb.PublicKey)
 	pbmes.Type = k.Type()
 	data, err := k.Raw()
@@ -297,8 +314,7 @@ func MarshalPublicKey(k PubKey) ([]byte, error) {
 		return nil, err
 	}
 	pbmes.Data = data
-
-	return proto.Marshal(pbmes)
+	return pbmes, nil
 }
 
 // UnmarshalPrivateKey converts a protobuf serialized private key into its

sec/insecure/insecure.go

@@ -5,64 +5,207 @@ package insecure
 
 import (
 	"context"
+	"fmt"
 	"net"
 
 	"github.com/libp2p/go-libp2p-core/peer"
 	"github.com/libp2p/go-libp2p-core/sec"
+	"github.com/libp2p/go-msgio"
 
 	ci "github.com/libp2p/go-libp2p-core/crypto"
+	pb "github.com/libp2p/go-libp2p-core/sec/insecure/pb"
 )
 
 // ID is the multistream-select protocol ID that should be used when identifying
 // this security transport.
-const ID = "/plaintext/1.0.0"
+const ID = "/plaintext/2.0.0"
 
 // Transport is a no-op stream security transport. It provides no
-// security and simply mocks the security and identity methods to
-// return peer IDs known ahead of time.
+// security and simply mocks the security methods. Identity methods
+// return the local peer's ID and private key, and whatever the remote
+// peer presents as their ID and public key.
+// No authentication of the remote identity is performed.
 type Transport struct {
-	id peer.ID
+	id  peer.ID
+	key ci.PrivKey
 }
 
 // New constructs a new insecure transport.
+// Deprecated: use NewWithIdentity instead.
 func New(id peer.ID) *Transport {
 	return &Transport{
 		id: id,
 	}
 }
 
-// LocalPeer returns the transports local peer ID.
+// New constructs a new insecure transport. The provided private key
+// is stored and returned from LocalPrivateKey to satisfy the
+// SecureTransport interface, and the public key is sent to
+// remote peers. No security is provided.
+func NewWithIdentity(id peer.ID, key ci.PrivKey) *Transport {
+	return &Transport{
+		id:  id,
+		key: key,
+	}
+}
+
+// LocalPeer returns the transport's local peer ID.
 func (t *Transport) LocalPeer() peer.ID {
 	return t.id
 }
 
-// LocalPrivateKey returns nil. This transport is not secure.
+// LocalPrivateKey returns the local private key.
+// This key is used only for identity generation and provides no security.
 func (t *Transport) LocalPrivateKey() ci.PrivKey {
-	return nil
+	return t.key
 }
 
 // SecureInbound *pretends to secure* an outbound connection to the given peer.
+// It sends the local peer's ID and public key, and receives the same from the remote peer.
+// No validation is performed as to the authenticity or ownership of the provided public key,
+// and the key exchange provides no security.
+//
+// SecureInbound may fail if the remote peer sends an ID and public key that are inconsistent
+// with each other, or if a network error occurs during the ID exchange.
 func (t *Transport) SecureInbound(ctx context.Context, insecure net.Conn) (sec.SecureConn, error) {
-	return &Conn{
-		Conn:  insecure,
-		local: t.id,
-	}, nil
+	conn := &Conn{
+		Conn:         insecure,
+		local:        t.id,
+		localPrivKey: t.key,
+	}
+
+	err := conn.runHandshakeSync()
+	if err != nil {
+		return nil, err
+	}
+
+	return conn, nil
 }
 
 // SecureOutbound *pretends to secure* an outbound connection to the given peer.
+// It sends the local peer's ID and public key, and receives the same from the remote peer.
+// No validation is performed as to the authenticity or ownership of the provided public key,
+// and the key exchange provides no security.
+//
+// SecureOutbound may fail if the remote peer sends an ID and public key that are inconsistent
+// with each other, or if the ID sent by the remote peer does not match the one dialed. It may
+// also fail if a network error occurs during the ID exchange.
 func (t *Transport) SecureOutbound(ctx context.Context, insecure net.Conn, p peer.ID) (sec.SecureConn, error) {
-	return &Conn{
-		Conn:   insecure,
-		local:  t.id,
-		remote: p,
-	}, nil
+	conn := &Conn{
+		Conn:         insecure,
+		local:        t.id,
+		localPrivKey: t.key,
+	}
+
+	err := conn.runHandshakeSync()
+	if err != nil {
+		return nil, err
+	}
+
+	if t.key != nil && p != conn.remote {
+		return nil, fmt.Errorf("remote peer sent unexpected peer ID. expected=%s received=%s",
+			p, conn.remote)
+	}
+
+	return conn, nil
 }
 
 // Conn is the connection type returned by the insecure transport.
 type Conn struct {
 	net.Conn
+
 	local  peer.ID
 	remote peer.ID
+
+	localPrivKey ci.PrivKey
+	remotePubKey ci.PubKey
+}
+
+func makeExchangeMessage(pubkey ci.PubKey) (*pb.Exchange, error) {
+	keyMsg, err := ci.PublicKeyToProto(pubkey)
+	if err != nil {
+		return nil, err
+	}
+	id, err := peer.IDFromPublicKey(pubkey)
+	if err != nil {
+		return nil, err
+	}
+
+	return &pb.Exchange{
+		Id:     []byte(id),
+		Pubkey: keyMsg,
+	}, nil
+}
+
+func (ic *Conn) runHandshakeSync() error {
+	// If we were initialized without keys, behave as in plaintext/1.0.0 (do nothing)
+	if ic.localPrivKey == nil {
+		return nil
+	}
+
+	rw := msgio.NewReadWriter(ic.Conn)
+	// Generate an Exchange message
+	msg, err := makeExchangeMessage(ic.localPrivKey.GetPublic())
+	if err != nil {
+		return err
+	}
+
+	// Send our Exchange and read theirs
+	remoteMsg, err := readWriteMsg(rw, msg)
+	if err != nil {
+		return err
+	}
+
+	// Pull remote ID and public key from message
+	remotePubkey, err := ci.PublicKeyFromProto(remoteMsg.Pubkey)
+	if err != nil {
+		return err
+	}
+
+	remoteID, err := peer.IDFromPublicKey(remotePubkey)
+	if err != nil {
+		return err
+	}
+
+	// Validate that ID matches public key
+	if !remoteID.MatchesPublicKey(remotePubkey) {
+		calculatedID, _ := peer.IDFromPublicKey(remotePubkey)
+		return fmt.Errorf("remote peer id does not match public key. id=%s calculated_id=%s",
+			remoteID, calculatedID)
+	}
+
+	// Add remote ID and key to conn state
+	ic.remotePubKey = remotePubkey
+	ic.remote = remoteID
+	return nil
+}
+
+// read and write a message at the same time.
+func readWriteMsg(c msgio.ReadWriter, out *pb.Exchange) (*pb.Exchange, error) {
+	outBytes, err := out.Marshal()
+	if err != nil {
+		return nil, err
+	}
+	wresult := make(chan error)
+	go func() {
+		wresult <- c.WriteMsg(outBytes)
+	}()
+
+	msg, err1 := c.ReadMsg()
+
+	// Always wait for the read to finish.
+	err2 := <-wresult
+
+	if err1 != nil {
+		return nil, err1
+	}
+	if err2 != nil {
+		c.ReleaseMsg(msg)
+		return nil, err2
+	}
+	inMsg := new(pb.Exchange)
+	err = inMsg.Unmarshal(msg)
+	return inMsg, err
 }
 
 // LocalPeer returns the local peer ID.
@@ -76,14 +219,15 @@ func (ic *Conn) RemotePeer() peer.ID {
 	return ic.remote
 }
 
-// RemotePublicKey returns nil. This connection is not secure
+// RemotePublicKey returns whatever public key was given by the remote peer.
+// Note that no verification of ownership is done, as this connection is not secure.
 func (ic *Conn) RemotePublicKey() ci.PubKey {
-	return nil
+	return ic.remotePubKey
 }
 
-// LocalPrivateKey returns nil. This connection is not secure.
+// LocalPrivateKey returns the private key for the local peer.
 func (ic *Conn) LocalPrivateKey() ci.PrivKey {
-	return nil
+	return ic.localPrivKey
 }
 
 var _ sec.SecureTransport = (*Transport)(nil)

sec/insecure/insecure_test.go

+package insecure
+
+import (
+	"bytes"
+	"context"
+	"github.com/libp2p/go-libp2p-core/peer"
+	"github.com/libp2p/go-libp2p-core/sec"
+	"io"
+	"net"
+	"testing"
+
+	ci "github.com/libp2p/go-libp2p-core/crypto"
+)
+
+// Run a set of sessions through the session setup and verification.
+func TestConnections(t *testing.T) {
+	clientTpt := newTestTransport(t, ci.RSA, 1024)
+	serverTpt := newTestTransport(t, ci.Ed25519, 1024)
+
+	testConnection(t, clientTpt, serverTpt)
+}
+
+func newTestTransport(t *testing.T, typ, bits int) *Transport {
+	priv, pub, err := ci.GenerateKeyPair(typ, bits)
+	if err != nil {
+		t.Fatal(err)
+	}
+	id, err := peer.IDFromPublicKey(pub)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return NewWithIdentity(id, priv)
+}
+
+// Create a new pair of connected TCP sockets.
+func newConnPair(t *testing.T) (net.Conn, net.Conn) {
+	lstnr, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		t.Fatalf("Failed to listen: %v", err)
+		return nil, nil
+	}
+
+	var clientErr error
+	var client net.Conn
+	addr := lstnr.Addr()
+	done := make(chan struct{})
+
+	go func() {
+		defer close(done)
+		client, clientErr = net.Dial(addr.Network(), addr.String())
+	}()
+
+	server, err := lstnr.Accept()
+	<-done
+
+	lstnr.Close()
+
+	if err != nil {
+		t.Fatalf("Failed to accept: %v", err)
+	}
+
+	if clientErr != nil {
+		t.Fatalf("Failed to connect: %v", clientErr)
+	}
+
+	return client, server
+}
+
+// Create a new pair of connected sessions based off of the provided
+// session generators.
+func connect(t *testing.T, clientTpt, serverTpt *Transport) (sec.SecureConn, sec.SecureConn) {
+	client, server := newConnPair(t)
+
+	// Connect the client and server sessions
+	done := make(chan struct{})
+
+	var clientConn sec.SecureConn
+	var clientErr error
+	go func() {
+		defer close(done)
+		clientConn, clientErr = clientTpt.SecureOutbound(context.TODO(), client, serverTpt.LocalPeer())
+	}()
+
+	serverConn, serverErr := serverTpt.SecureInbound(context.TODO(), server)
+	<-done
+
+	if serverErr != nil {
+		t.Fatal(serverErr)
+	}
+
+	if clientErr != nil {
+		t.Fatal(clientErr)
+	}
+
+	return clientConn, serverConn
+}
+
+// Check the peer IDs
+func testIDs(t *testing.T, clientTpt, serverTpt *Transport, clientConn, serverConn sec.SecureConn) {
+	if clientConn.LocalPeer() != clientTpt.LocalPeer() {
+		t.Fatal("Client Local Peer ID mismatch.")
+	}
+
+	if clientConn.RemotePeer() != serverTpt.LocalPeer() {
+		t.Fatal("Client Remote Peer ID mismatch.")
+	}
+
+	if clientConn.LocalPeer() != serverConn.RemotePeer() {
+		t.Fatal("Server Local Peer ID mismatch.")
+	}
+}
+
+// Check the keys
+func testKeys(t *testing.T, clientTpt, serverTpt *Transport, clientConn, serverConn sec.SecureConn) {
+	sk := serverConn.LocalPrivateKey()
+	pk := sk.GetPublic()
+
+	if !sk.Equals(serverTpt.LocalPrivateKey()) {
+		t.Error("Private key Mismatch.")
+	}
+
+	if !pk.Equals(clientConn.RemotePublicKey()) {
+		t.Error("Public key mismatch.")
+	}
+}
+
+// Check sending and receiving messages
+func testReadWrite(t *testing.T, clientConn, serverConn sec.SecureConn) {
+	before := []byte("hello world")
+	_, err := clientConn.Write(before)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	after := make([]byte, len(before))
+	_, err = io.ReadFull(serverConn, after)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !bytes.Equal(before, after) {
+		t.Errorf("Message mismatch. %v != %v", before, after)
+	}
+}
+
+// Setup a new session with a pair of locally connected sockets
+func testConnection(t *testing.T, clientTpt, serverTpt *Transport) {
+	clientConn, serverConn := connect(t, clientTpt, serverTpt)
+
+	testIDs(t, clientTpt, serverTpt, clientConn, serverConn)
+	testKeys(t, clientTpt, serverTpt, clientConn, serverConn)
+	testReadWrite(t, clientConn, serverConn)
+
+	clientConn.Close()
+	serverConn.Close()
+}

sec/insecure/pb/Makefile

+PB = $(wildcard *.proto)
+GO = $(PB:.proto=.pb.go)
+
+all: $(GO)
+
+%.pb.go: %.proto
+		protoc --proto_path=$(GOPATH)/src:../../../crypto/pb:. --gogofaster_out=. $<
+
+clean:
+		rm -f *.pb.go
+		rm -f *.go

sec/insecure/pb/plaintext.pb.go

+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: plaintext.proto
+
+package plaintext_pb
+
+import (
+	fmt "fmt"
+	proto "github.com/gogo/protobuf/proto"
+	pb "github.com/libp2p/go-libp2p-core/crypto/pb"
+	io "io"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.GoGoProtoPackageIsVersion2 // please upgrade the proto package
+
+type Exchange struct {
+	Id     []byte        `protobuf:"bytes,1,opt,name=id" json:"id"`
+	Pubkey *pb.PublicKey `protobuf:"bytes,2,opt,name=pubkey" json:"pubkey,omitempty"`
+}
+
+func (m *Exchange) Reset()         { *m = Exchange{} }
+func (m *Exchange) String() string { return proto.CompactTextString(m) }
+func (*Exchange) ProtoMessage()    {}
+func (*Exchange) Descriptor() ([]byte, []int) {
+	return fileDescriptor_aba144f73931b711, []int{0}
+}
+func (m *Exchange) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *Exchange) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_Exchange.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *Exchange) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Exchange.Merge(m, src)
+}
+func (m *Exchange) XXX_Size() int {
+	return m.Size()
+}
+func (m *Exchange) XXX_DiscardUnknown() {
+	xxx_messageInfo_Exchange.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Exchange proto.InternalMessageInfo
+
+func (m *Exchange) GetId() []byte {
+	if m != nil {
+		return m.Id
+	}
+	return nil
+}
+
+func (m *Exchange) GetPubkey() *pb.PublicKey {
+	if m != nil {
+		return m.Pubkey
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*Exchange)(nil), "plaintext.pb.Exchange")
+}
+
+func init() { proto.RegisterFile("plaintext.proto", fileDescriptor_aba144f73931b711) }
+
+var fileDescriptor_aba144f73931b711 = []byte{
+	// 187 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0xe2, 0x2f, 0xc8, 0x49, 0xcc,
+	0xcc, 0x2b, 0x49, 0xad, 0x28, 0xd1, 0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0xe2, 0x41, 0x12, 0x48,
+	0x92, 0x32, 0x4f, 0xcf, 0x2c, 0xc9, 0x28, 0x4d, 0xd2, 0x4b, 0xce, 0xcf, 0xd5, 0xcf, 0xc9, 0x4c,
+	0x2a, 0x30, 0x2a, 0xd0, 0x4f, 0xcf, 0xd7, 0x85, 0xb0, 0x74, 0x93, 0xf3, 0x8b, 0x52, 0xf5, 0x93,
+	0x8b, 0x2a, 0x0b, 0x4a, 0xf2, 0xf5, 0x0b, 0x92, 0xa0, 0x2c, 0x88, 0x31, 0x4a, 0x7e, 0x5c, 0x1c,
+	0xae, 0x15, 0xc9, 0x19, 0x89, 0x79, 0xe9, 0xa9, 0x42, 0x22, 0x5c, 0x4c, 0x99, 0x29, 0x12, 0x8c,
+	0x0a, 0x8c, 0x1a, 0x3c, 0x4e, 0x2c, 0x27, 0xee, 0xc9, 0x33, 0x04, 0x31, 0x65, 0xa6, 0x08, 0xe9,
+	0x70, 0xb1, 0x15, 0x94, 0x26, 0x65, 0xa7, 0x56, 0x4a, 0x30, 0x29, 0x30, 0x6a, 0x70, 0x1b, 0x89,
+	0xe8, 0xc1, 0x0c, 0x48, 0xd2, 0x0b, 0x28, 0x4d, 0xca, 0xc9, 0x4c, 0xf6, 0x4e, 0xad, 0x0c, 0x82,
+	0xaa, 0x71, 0x92, 0x38, 0xf1, 0x48, 0x8e, 0xf1, 0xc2, 0x23, 0x39, 0xc6, 0x07, 0x8f, 0xe4, 0x18,
+	0x27, 0x3c, 0x96, 0x63, 0xb8, 0xf0, 0x58, 0x8e, 0xe1, 0xc6, 0x63, 0x39, 0x06, 0x40, 0x00, 0x00,
+	0x00, 0xff, 0xff, 0x40, 0xde, 0x90, 0x0b, 0xc2, 0x00, 0x00, 0x00,
+}
+
+func (m *Exchange) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Exchange) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.Id != nil {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintPlaintext(dAtA, i, uint64(len(m.Id)))
+		i += copy(dAtA[i:], m.Id)
+	}
+	if m.Pubkey != nil {
+		dAtA[i] = 0x12
+		i++
+		i = encodeVarintPlaintext(dAtA, i, uint64(m.Pubkey.Size()))
+		n1, err := m.Pubkey.MarshalTo(dAtA[i:])
+		if err != nil {
+			return 0, err
+		}
+		i += n1
+	}
+	return i, nil
+}
+
+func encodeVarintPlaintext(dAtA []byte, offset int, v uint64) int {
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return offset + 1
+}
+func (m *Exchange) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Id != nil {
+		l = len(m.Id)
+		n += 1 + l + sovPlaintext(uint64(l))
+	}
+	if m.Pubkey != nil {
+		l = m.Pubkey.Size()
+		n += 1 + l + sovPlaintext(uint64(l))
+	}
+	return n
+}
+
+func sovPlaintext(x uint64) (n int) {
+	for {
+		n++
+		x >>= 7
+		if x == 0 {
+			break
+		}
+	}
+	return n
+}
+func sozPlaintext(x uint64) (n int) {
+	return sovPlaintext(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *Exchange) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowPlaintext
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Exchange: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Exchange: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Id", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowPlaintext
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthPlaintext
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthPlaintext
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Id = append(m.Id[:0], dAtA[iNdEx:postIndex]...)
+			if m.Id == nil {
+				m.Id = []byte{}
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Pubkey", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowPlaintext
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthPlaintext
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthPlaintext
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Pubkey == nil {
+				m.Pubkey = &pb.PublicKey{}
+			}
+			if err := m.Pubkey.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipPlaintext(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthPlaintext
+			}
+			if (iNdEx + skippy) < 0 {
+				return ErrInvalidLengthPlaintext
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipPlaintext(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowPlaintext
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowPlaintext
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+			return iNdEx, nil
+		case 1:
+			iNdEx += 8
+			return iNdEx, nil
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowPlaintext
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthPlaintext
+			}
+			iNdEx += length
+			if iNdEx < 0 {
+				return 0, ErrInvalidLengthPlaintext
+			}
+			return iNdEx, nil
+		case 3:
+			for {
+				var innerWire uint64
+				var start int = iNdEx
+				for shift := uint(0); ; shift += 7 {
+					if shift >= 64 {
+						return 0, ErrIntOverflowPlaintext
+					}
+					if iNdEx >= l {
+						return 0, io.ErrUnexpectedEOF
+					}
+					b := dAtA[iNdEx]
+					iNdEx++
+					innerWire |= (uint64(b) & 0x7F) << shift
+					if b < 0x80 {
+						break
+					}
+				}
+				innerWireType := int(innerWire & 0x7)
+				if innerWireType == 4 {
+					break
+				}
+				next, err := skipPlaintext(dAtA[start:])
+				if err != nil {
+					return 0, err
+				}
+				iNdEx = start + next
+				if iNdEx < 0 {
+					return 0, ErrInvalidLengthPlaintext
+				}
+			}
+			return iNdEx, nil
+		case 4:
+			return iNdEx, nil
+		case 5:
+			iNdEx += 4
+			return iNdEx, nil
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+	}
+	panic("unreachable")
+}
+
+var (
+	ErrInvalidLengthPlaintext = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowPlaintext   = fmt.Errorf("proto: integer overflow")
+)

sec/insecure/pb/plaintext.proto

+syntax = "proto2";
+
+package plaintext.pb;
+
+import "github.com/libp2p/go-libp2p-core/crypto/pb/crypto.proto";
+
+message Exchange {
+    optional bytes id = 1;
+    optional crypto.pb.PublicKey pubkey = 2;
+}