diff --git a/FirebaseAdmin/FirebaseAdmin/Auth/FirebaseTokenVerifier.cs b/FirebaseAdmin/FirebaseAdmin/Auth/FirebaseTokenVerifier.cs
index 4e0c55d1..210b8767 100644
--- a/FirebaseAdmin/FirebaseAdmin/Auth/FirebaseTokenVerifier.cs
+++ b/FirebaseAdmin/FirebaseAdmin/Auth/FirebaseTokenVerifier.cs
@@ -40,6 +40,9 @@ internal sealed class FirebaseTokenVerifier
         private static readonly IReadOnlyList<string> StandardClaims =
             ImmutableList.Create<string>("iss", "aud", "exp", "iat", "sub", "uid");
 
+        // See http://oid-info.com/get/2.16.840.1.101.3.4.2.1
+        private const string Sha256Oid = "2.16.840.1.101.3.4.2.1";
+
         public string ProjectId { get; }
         private readonly string _shortName;
         private readonly string _articledShortName;
@@ -172,8 +175,17 @@ private async Task VerifySignatureAsync(
             var keys = await _keySource.GetPublicKeysAsync(cancellationToken)
                 .ConfigureAwait(false);
             var verified = keys.Any(key =>
-                key.Id == keyId && key.RSA.VerifyHash(
-                    hash, signature, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1));
+            {
+#if NETSTANDARD1_5 || NETSTANDARD2_0                
+                return key.Id == keyId && key.RSA.VerifyHash(
+                    hash, signature, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
+#elif NET45
+                return key.Id == keyId && 
+                    ((RSACryptoServiceProvider) key.RSA).VerifyHash(hash, Sha256Oid, signature);
+#else
+#error Unsupported target
+#endif  
+            });
             if (!verified)
             {
                 throw new FirebaseException($"Failed to verify {_shortName} signature.");
diff --git a/FirebaseAdmin/FirebaseAdmin/Auth/HttpPublicKeySource.cs b/FirebaseAdmin/FirebaseAdmin/Auth/HttpPublicKeySource.cs
index 1d1f77a3..4ddd0abf 100644
--- a/FirebaseAdmin/FirebaseAdmin/Auth/HttpPublicKeySource.cs
+++ b/FirebaseAdmin/FirebaseAdmin/Auth/HttpPublicKeySource.cs
@@ -26,6 +26,14 @@
 using Google.Apis.Http;
 using Google.Apis.Util;
 
+#if NETSTANDARD1_5 || NETSTANDARD2_0
+using RsaKey = System.Security.Cryptography.RSA;
+#elif NET45
+using RsaKey = System.Security.Cryptography.RSACryptoServiceProvider;
+#else
+#error Unsupported target
+#endif  
+
 namespace FirebaseAdmin.Auth
 {
     /// <summary>
@@ -104,7 +112,14 @@ private IReadOnlyList<PublicKey> ParseKeys(string json)
             foreach (var entry in rawKeys)
             {
                 var x509cert = new X509Certificate2(Encoding.UTF8.GetBytes(entry.Value));
-                var rsa = x509cert.GetRSAPublicKey();
+                RsaKey rsa;
+#if NETSTANDARD1_5 || NETSTANDARD2_0
+                rsa = x509cert.GetRSAPublicKey();
+#elif NET45
+                rsa = (RSACryptoServiceProvider) x509cert.PublicKey.Key;
+#else
+#error Unsupported target
+#endif                
                 builder.Add(new PublicKey(entry.Key, rsa));
             }
             return builder.ToImmutableList();
diff --git a/FirebaseAdmin/FirebaseAdmin/Auth/PublicKey.cs b/FirebaseAdmin/FirebaseAdmin/Auth/PublicKey.cs
index d6639765..158d7e0f 100644
--- a/FirebaseAdmin/FirebaseAdmin/Auth/PublicKey.cs
+++ b/FirebaseAdmin/FirebaseAdmin/Auth/PublicKey.cs
@@ -12,7 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-using System.Security.Cryptography;
+#if NETSTANDARD1_5 || NETSTANDARD2_0
+using RsaKey = System.Security.Cryptography.RSA;
+#elif NET45
+using RsaKey = System.Security.Cryptography.RSACryptoServiceProvider;
+#else
+#error Unsupported target
+#endif  
 
 namespace FirebaseAdmin.Auth
 {
@@ -30,9 +36,9 @@ internal sealed class PublicKey
         /// A <see cref="System.Security.Cryptography.RSA"/> instance containing the contents of
         /// the public key.
         /// </summary>
-        public RSA RSA { get; }
+        public RsaKey RSA { get; }
 
-        public PublicKey(string keyId, RSA rsa)
+        public PublicKey(string keyId, RsaKey rsa)
         {
             Id = keyId;
             RSA = rsa;
diff --git a/appveyor.yml b/appveyor.yml
new file mode 100644
index 00000000..a98bb516
--- /dev/null
+++ b/appveyor.yml
@@ -0,0 +1,24 @@
+version: '1.0.{build}'
+image:
+   - Visual Studio 2017
+   - Ubuntu
+init:
+  # Good practise, because Windows line endings are different from Unix/Linux ones
+  - cmd: git config --global core.autocrlf true
+install:
+  # Install repo specific stuff here
+before_build:
+  # Display .NET Core version
+  - dotnet --version
+  # Display minimal restore text
+  - dotnet restore FirebaseAdmin/FirebaseAdmin.sln --verbosity m
+build_script:
+  - dotnet build FirebaseAdmin
+after_build:
+  # For once the build has completed
+clone_depth: 1
+test_script:
+  - dotnet test FirebaseAdmin/FirebaseAdmin.Tests
+on_finish :
+  # any cleanup in here
+deploy: off
\ No newline at end of file