diff --git a/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime.Azure.Authentication/CertificateAuthenticationProvider.cs b/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime.Azure.Authentication/CertificateAuthenticationProvider.cs
index ac3e34037f83d..f619dc5e85ed5 100644
--- a/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime.Azure.Authentication/CertificateAuthenticationProvider.cs
+++ b/ClientRuntimes/CSharp/Microsoft.Rest.ClientRuntime.Azure.Authentication/CertificateAuthenticationProvider.cs
@@ -1,4 +1,7 @@
-using System;
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
 using System.Threading.Tasks;
 using Microsoft.IdentityModel.Clients.ActiveDirectory;