diff --git a/transport/vless/addons.go b/transport/vless/addons.go
new file mode 100644
index 00000000..2257adeb
--- /dev/null
+++ b/transport/vless/addons.go
@@ -0,0 +1,61 @@
+package vless
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+func ReadAddons(data []byte) (*Addons, error) {
+	reader := bytes.NewReader(data)
+	var addons Addons
+	for reader.Len() > 0 {
+		protoHeader, err := reader.ReadByte()
+		if err != nil {
+			return nil, err
+		}
+		switch protoHeader {
+		case (1 << 3) | 2:
+			flowLen, err := binary.ReadUvarint(reader)
+			if err != nil {
+				return nil, err
+			}
+			flowBytes := make([]byte, flowLen)
+			_, err = io.ReadFull(reader, flowBytes)
+			if err != nil {
+				return nil, err
+			}
+			addons.Flow = string(flowBytes)
+		case (2 << 3) | 2:
+			seedLen, err := binary.ReadUvarint(reader)
+			if err != nil {
+				return nil, err
+			}
+			seedBytes := make([]byte, seedLen)
+			_, err = io.ReadFull(reader, seedBytes)
+			if err != nil {
+				return nil, err
+			}
+			addons.Seed = seedBytes
+		default:
+			return nil, fmt.Errorf("unknown protobuf message header: %v", protoHeader)
+		}
+	}
+	return &addons, nil
+}
+
+func WriteAddons(addons *Addons) []byte {
+	var writer bytes.Buffer
+	if len(addons.Flow) > 0 {
+		writer.WriteByte((1 << 3) | 2)
+		writer.Write(binary.AppendUvarint(nil, uint64(len(addons.Flow))))
+		writer.WriteString(addons.Flow)
+	}
+	if len(addons.Seed) > 0 {
+		writer.WriteByte((2 << 3) | 2)
+		writer.Write(binary.AppendUvarint(nil, uint64(len(addons.Seed))))
+		writer.Write(addons.Seed)
+	}
+	return writer.Bytes()
+}
diff --git a/transport/vless/addons_test.go b/transport/vless/addons_test.go
new file mode 100644
index 00000000..60a27a06
--- /dev/null
+++ b/transport/vless/addons_test.go
@@ -0,0 +1,95 @@
+package vless
+
+import (
+	"bytes"
+	"strconv"
+	"testing"
+
+	"google.golang.org/protobuf/proto"
+)
+
+func TestAddons(t *testing.T) {
+	var tests = []struct {
+		flow string
+		seed []byte
+	}{
+		{XRV, nil},
+		{XRS, []byte{1, 2, 3}},
+		{"", []byte{1, 2, 3}},
+		{"", nil},
+	}
+
+	for i, test := range tests {
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
+			t.Run("proto->handwritten", func(t *testing.T) {
+				addons := new(Addons)
+				addons.Flow = test.flow
+				addons.Seed = test.seed
+
+				addonsBytes, err := proto.Marshal(addons)
+				if err != nil {
+					t.Errorf("error marshalling addons: %v", err)
+					return
+				}
+				addons, err = ReadAddons(addonsBytes)
+				if err != nil {
+					t.Errorf("error reading addons: %v", err)
+					return
+				}
+
+				if addons.Flow != test.flow {
+					t.Errorf("got %v; want %v", addons.Flow, test.flow)
+					return
+				}
+				if !bytes.Equal(addons.Seed, test.seed) {
+					t.Errorf("got %v; want %v", addons.Seed, test.seed)
+					return
+				}
+			})
+
+			t.Run("handwritten->proto", func(t *testing.T) {
+				addons := new(Addons)
+				addons.Flow = test.flow
+				addons.Seed = test.seed
+
+				addonsBytes := WriteAddons(addons)
+				err := proto.Unmarshal(addonsBytes, addons)
+				if err != nil {
+					t.Errorf("error reading addons: %v", err)
+					return
+				}
+
+				if addons.Flow != test.flow {
+					t.Errorf("got %v; want %v", addons.Flow, test.flow)
+					return
+				}
+				if !bytes.Equal(addons.Seed, test.seed) {
+					t.Errorf("got %v; want %v", addons.Seed, test.seed)
+					return
+				}
+			})
+
+			t.Run("handwritten->handwritten", func(t *testing.T) {
+				addons := new(Addons)
+				addons.Flow = test.flow
+				addons.Seed = test.seed
+
+				addonsBytes := WriteAddons(addons)
+				addons, err := ReadAddons(addonsBytes)
+				if err != nil {
+					t.Errorf("error reading addons: %v", err)
+					return
+				}
+
+				if addons.Flow != test.flow {
+					t.Errorf("got %v; want %v", addons.Flow, test.flow)
+					return
+				}
+				if !bytes.Equal(addons.Seed, test.seed) {
+					t.Errorf("got %v; want %v", addons.Seed, test.seed)
+					return
+				}
+			})
+		})
+	}
+}
diff --git a/transport/vless/vision/conn.go b/transport/vless/vision/conn.go
index 2801091c..fd9f787b 100644
--- a/transport/vless/vision/conn.go
+++ b/transport/vless/vision/conn.go
@@ -2,7 +2,6 @@ package vision
 
 import (
 	"bytes"
-	"crypto/subtle"
 	"encoding/binary"
 	"errors"
 	"fmt"
@@ -57,8 +56,8 @@ func (vc *Conn) Read(b []byte) (int, error) {
 }
 
 func (vc *Conn) ReadBuffer(buffer *buf.Buffer) error {
-	toRead := buffer.FreeBytes()
 	if vc.readRemainingContent > 0 {
+		toRead := buffer.FreeBytes()
 		if vc.readRemainingContent < buffer.FreeLen() {
 			toRead = toRead[:vc.readRemainingContent]
 		}
@@ -79,12 +78,12 @@ func (vc *Conn) ReadBuffer(buffer *buf.Buffer) error {
 		switch vc.readLastCommand {
 		case commandPaddingContinue:
 			//if vc.isTLS || vc.packetsToFilter > 0 {
-			headerUUIDLen := 0
-			if vc.readFilterUUID {
-				headerUUIDLen = uuid.Size
+			need := PaddingHeaderLen
+			if !vc.readFilterUUID {
+				need = PaddingHeaderLen - uuid.Size
 			}
 			var header []byte
-			if need := headerUUIDLen + PaddingHeaderLen - uuid.Size; buffer.FreeLen() < need {
+			if buffer.FreeLen() < need {
 				header = make([]byte, need)
 			} else {
 				header = buffer.FreeBytes()[:need]
@@ -95,9 +94,8 @@ func (vc *Conn) ReadBuffer(buffer *buf.Buffer) error {
 			}
 			if vc.readFilterUUID {
 				vc.readFilterUUID = false
-				if subtle.ConstantTimeCompare(vc.userUUID.Bytes(), header[:uuid.Size]) != 1 {
-					err = fmt.Errorf("XTLS Vision server responded unknown UUID: %s",
-						uuid.FromBytesOrNil(header[:uuid.Size]).String())
+				if !bytes.Equal(vc.userUUID.Bytes(), header[:uuid.Size]) {
+					err = fmt.Errorf("XTLS Vision server responded unknown UUID: %s", uuid.FromBytesOrNil(header[:uuid.Size]))
 					log.Errorln(err.Error())
 					return err
 				}
@@ -180,7 +178,7 @@ func (vc *Conn) WriteBuffer(buffer *buf.Buffer) (err error) {
 		for i, buffer := range buffers {
 			command := commandPaddingContinue
 			if applyPadding {
-				if vc.isTLS && buffer.Len() > 6 && bytes.Equal(buffer.To(3), tlsApplicationDataStart) {
+				if vc.isTLS && buffer.Len() > 6 && bytes.Equal(tlsApplicationDataStart, buffer.To(3)) {
 					command = commandPaddingEnd
 					if vc.enableXTLS {
 						command = commandPaddingDirect
diff --git a/transport/vless/vision/padding.go b/transport/vless/vision/padding.go
index 3152139a..38609552 100644
--- a/transport/vless/vision/padding.go
+++ b/transport/vless/vision/padding.go
@@ -5,8 +5,8 @@ import (
 	"encoding/binary"
 
 	"github.com/metacubex/mihomo/common/buf"
+	N "github.com/metacubex/mihomo/common/net"
 	"github.com/metacubex/mihomo/log"
-	N "github.com/metacubex/sing/common/network"
 
 	"github.com/gofrs/uuid/v5"
 	"github.com/metacubex/randv2"