diff --git a/IpcStream.cs b/IpcStream.cs
index 729dde1..ae63f8e 100644
--- a/IpcStream.cs
+++ b/IpcStream.cs
@@ -33,6 +33,7 @@ public class IpcStream : IDisposable
 
         private bool _disposed = false;
         protected bool encrypted = false;
+        private object _lockObject = new object();
 
         /// <summary>
         /// Constructor
@@ -119,16 +120,19 @@ protected async Task<byte[]> ReadBytesAsync()
         /// <param name="buffer">byte buffer</param>
         protected void WriteBytes(byte[] buffer)
         {
-            int length = buffer.Length;
-            if (length > UInt16.MaxValue)
-                throw new InvalidOperationException("Message is too long");
+            lock (_lockObject)
+            {
+                int length = buffer.Length;
+                if (length > UInt16.MaxValue)
+                    throw new InvalidOperationException("Message is too long");
 
-            // write message length
-            BaseStream.Write(new byte[] { (byte)(length / 256), (byte)(length & 255) }, 0, 2);
+                // write message length
+                BaseStream.Write(new byte[] {(byte) (length / 256), (byte) (length % 256)}, 0, 2);
 
-            // write message
-            BaseStream.Write(buffer, 0, length);
-            BaseStream.Flush();
+                // write message
+                BaseStream.Write(buffer, 0, length);
+                BaseStream.Flush();
+            }
         }
 
         /// <summary>