diff --git a/pkg/obfs/xplus.go b/pkg/obfs/xplus.go
index a836411..b1484d6 100644
--- a/pkg/obfs/xplus.go
+++ b/pkg/obfs/xplus.go
@@ -7,7 +7,9 @@ import (
 	"time"
 )
 
-// [salt(16)][obfuscated payload]
+// [salt][obfuscated payload]
+
+const saltLen = 16
 
 type XPlusObfuscator struct {
 	Key     []byte
@@ -24,14 +26,14 @@ func NewXPlusObfuscator(key []byte) *XPlusObfuscator {
 }
 
 func (x *XPlusObfuscator) Deobfuscate(in []byte, out []byte) int {
-	pLen := len(in) - 16
+	pLen := len(in) - saltLen
 	if pLen <= 0 || len(out) < pLen {
 		// Invalid
 		return 0
 	}
-	key := sha256.Sum256(append(x.Key, in[:16]...))
+	key := sha256.Sum256(append(x.Key, in[:saltLen]...))
 	// Deobfuscate the payload
-	for i, c := range in[16:] {
+	for i, c := range in[saltLen:] {
 		out[i] = c ^ key[i%sha256.Size]
 	}
 	return pLen
@@ -39,14 +41,14 @@ func (x *XPlusObfuscator) Deobfuscate(in []byte, out []byte) int {
 
 func (x *XPlusObfuscator) Obfuscate(p []byte) []byte {
 	pLen := len(p)
-	buf := make([]byte, 16+pLen)
+	buf := make([]byte, saltLen+pLen)
 	x.lk.Lock()
-	_, _ = x.RandSrc.Read(buf[:16]) // salt
+	_, _ = x.RandSrc.Read(buf[:saltLen]) // salt
 	x.lk.Unlock()
 	// Obfuscate the payload
-	key := sha256.Sum256(append(x.Key, buf[:16]...))
+	key := sha256.Sum256(append(x.Key, buf[:saltLen]...))
 	for i, c := range p {
-		buf[i+16] = c ^ key[i%sha256.Size]
+		buf[i+saltLen] = c ^ key[i%sha256.Size]
 	}
 	return buf
 }