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diff --git a/src/csharp/Grpc.Auth/GoogleCredential.cs b/src/csharp/Grpc.Auth/GoogleCredential.cs
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+++ b/src/csharp/Grpc.Auth/GoogleCredential.cs
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+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Security.Cryptography;
+
+using Google.Apis.Auth.OAuth2;
+using Mono.Security.Cryptography;
+using Newtonsoft.Json.Linq;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+
+namespace Grpc.Auth
+{
+    // TODO(jtattermusch): Remove this class once possible.
+    /// <summary>
+    /// A temporary placeholder for Google credential from 
+    /// Google Auth library for .NET. It emulates the usage pattern 
+    /// for Usable auth.
+    /// </summary>
+    public class GoogleCredential
+    {
+        private const string GoogleApplicationCredentialsEnvName = "GOOGLE_APPLICATION_CREDENTIALS";
+        private const string ClientEmailFieldName = "client_email";
+        private const string PrivateKeyFieldName = "private_key";
+
+        private ServiceCredential credential;
+
+        private GoogleCredential(ServiceCredential credential)
+        {
+            this.credential = credential;
+        }
+
+        public static GoogleCredential GetApplicationDefault()
+        {
+            return new GoogleCredential(null);  
+        }
+
+        public bool IsCreateScopedRequired
+        {
+            get
+            {
+                return true;
+            }
+        }
+
+        public GoogleCredential CreateScoped(IEnumerable<string> scopes)
+        {
+            var credsPath = Environment.GetEnvironmentVariable(GoogleApplicationCredentialsEnvName);
+            if (credsPath == null)
+            {
+                // Default to ComputeCredentials if path to JSON key is not set.
+                // ComputeCredential is not scoped actually, but for our use case it's
+                // fine to treat is as such.
+                return new GoogleCredential(new ComputeCredential(new ComputeCredential.Initializer()));
+            }
+
+            JObject o1 = JObject.Parse(File.ReadAllText(credsPath));
+            string clientEmail = o1.GetValue(ClientEmailFieldName).Value<string>();
+            string privateKeyString = o1.GetValue(PrivateKeyFieldName).Value<string>();
+            var privateKey = ParsePrivateKeyFromString(privateKeyString);
+
+            var serviceCredential = new ServiceAccountCredential(
+                new ServiceAccountCredential.Initializer(clientEmail)
+                {
+                    Scopes = scopes,
+                    Key = privateKey
+                });
+            return new GoogleCredential(serviceCredential);
+        }
+
+        internal ServiceCredential InternalCredential
+        {
+            get
+            {
+                return credential;
+            }
+        }
+
+        private RSACryptoServiceProvider ParsePrivateKeyFromString(string base64PrivateKey)
+        {
+            // TODO(jtattermusch): temporary code to create RSACryptoServiceProvider.
+            base64PrivateKey = base64PrivateKey.Replace("-----BEGIN PRIVATE KEY-----", "").Replace("\n", "").Replace("-----END PRIVATE KEY-----", "");
+            PKCS8.PrivateKeyInfo PKI = new PKCS8.PrivateKeyInfo(Convert.FromBase64String(base64PrivateKey));
+            RsaPrivateCrtKeyParameters key = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(PKI.GetBytes());
+            RSAParameters rsaParameters = DotNetUtilities.ToRSAParameters(key);
+            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
+            rsa.ImportParameters(rsaParameters);
+            return rsa;
+        }
+    }
+}