implemented test for fingerprint auth

src/FingerprintTest/FingerprintModule.cs

@@ -9,8 +9,11 @@ using Android.Hardware.Fingerprints;
 using Android.OS;
 using Android.Security.Keystore;
 using Android.Preferences;
+using Android.Util;
+using Android.Widget;
 using Java.IO;
 using Java.Security.Cert;
+using Javax.Crypto.Spec;
 
 namespace keepass2android
 {
@@ -25,7 +28,7 @@ namespace keepass2android
 
 		public FingerprintManager FingerprintManager 
 		{
-			get { return (FingerprintManager) Context.GetSystemService("FingerprintManager"); }
+			get { return (FingerprintManager) Context.GetSystemService(Context.FingerprintService); }
 		}
 
 		public KeyguardManager KeyguardManager 
@@ -103,8 +106,9 @@ namespace keepass2android
 		}
 	}
 
-	public class FingerprintEncryptionModule: FingerprintManager.AuthenticationCallback
+	public abstract class FingerprintCrypt: FingerprintManager.AuthenticationCallback
 	{
+		protected const string FailedToInitCipher = "Failed to init Cipher";
 		public override void OnAuthenticationError(FingerprintState errorCode, ICharSequence errString)
 		{
 			_callback.OnAuthenticationError(errorCode, errString);
@@ -126,37 +130,191 @@ namespace keepass2android
 			_callback.OnAuthenticationSucceeded(result);
 		}
 
-		private readonly FingerprintModule _fingerprint;
+		protected readonly string _keyId;
-		private readonly string _keyId;
+
-		private Cipher _cipher;
+		protected Cipher _cipher;
 		private bool _selfCancelled;
 		private CancellationSignal _cancellationSignal;
-		private FingerprintManager.CryptoObject _cryptoObject;
+		protected FingerprintManager.CryptoObject _cryptoObject;
 		private FingerprintManager.AuthenticationCallback _callback;
+		protected KeyStore _keystore;
+		
+		private FingerprintManager _fingerprintManager;
 
-		public FingerprintEncryptionModule(FingerprintModule fingerprint, string keyId)
+		public FingerprintCrypt(FingerprintModule fingerprint, string keyId)
 		{
-			_fingerprint = fingerprint;
+			
 			_keyId = keyId;
+			
 			_cipher = fingerprint.Cipher;
+			_keystore = fingerprint.Keystore;
+			
+			_fingerprintManager = fingerprint.FingerprintManager;
+			
+		}
+
+		public abstract bool InitCipher();
+		protected static string GetAlias(string keyId)
+		{
+			return "keepass2android." + keyId;
+		}
+		protected static string GetIvPrefKey(string prefKey)
+		{
+			return prefKey + "_iv";
+		}
+		public bool IsFingerprintAuthAvailable
+		{
+			get
+			{
+				return _fingerprintManager.IsHardwareDetected
+					&& _fingerprintManager.HasEnrolledFingerprints;
+			}
+		}
+
+		public void StartListening(FingerprintManager.AuthenticationCallback callback)
+		{
+			if (!IsFingerprintAuthAvailable)
+				return;
+
+			_cancellationSignal = new CancellationSignal();
+			_selfCancelled = false;
+			_callback = callback;
+			_fingerprintManager.Authenticate(_cryptoObject, _cancellationSignal, 0 /* flags */, this, null);
+			
+		}
+
+		public void StopListening()
+		{
+			if (_cancellationSignal != null)
+			{
+				_selfCancelled = true;
+				_cancellationSignal.Cancel();
+				_cancellationSignal = null;
+			}
+		}
+
+		public string Encrypt(string textToEncrypt)
+		{
+			return Base64.EncodeToString(_cipher.DoFinal(System.Text.Encoding.UTF8.GetBytes(textToEncrypt)), 0);
+		}
+
+
+		public void StoreEncrypted(string textToEncrypt, string prefKey, Context context)
+		{
+			var edit = PreferenceManager.GetDefaultSharedPreferences(context).Edit();
+
+			edit.PutString(prefKey, Encrypt(textToEncrypt));
+			edit.PutString(GetIvPrefKey(prefKey), Base64.EncodeToString(CipherIv,0));
+			edit.Commit();
+		}
+
+		
+
+		private byte[] CipherIv
+		{
+			get { return _cipher.GetIV(); }
+		}
+	}
+
+	public class FingerprintDecryption : FingerprintCrypt
+	{
+		private readonly byte[] _iv;
+		
+
+		public FingerprintDecryption(FingerprintModule fingerprint, string keyId, byte[] iv) : base(fingerprint, keyId)
+		{
+			_iv = iv;
+		}
+
+		public FingerprintDecryption(FingerprintModule fingerprint, string keyId, Context context, string prefKey)
+			: base(fingerprint, keyId)
+		{
+			_iv = Base64.Decode(PreferenceManager.GetDefaultSharedPreferences(context).GetString(GetIvPrefKey(prefKey), null), 0);
+		}
+
+		public override bool InitCipher()
+		{
+			
+			try
+			{
+				_keystore.Load(null);
+				var key = _keystore.GetKey(GetAlias(_keyId), null);
+				var ivParams = new IvParameterSpec(_iv);
+				_cipher.Init(CipherMode.DecryptMode, key, ivParams);
+
+				_cryptoObject = new FingerprintManager.CryptoObject(_cipher);
+				return true;
+			}
+			catch (KeyPermanentlyInvalidatedException)
+			{
+				return false;
+			}
+			catch (KeyStoreException e)
+			{
+				throw new RuntimeException(FailedToInitCipher, e);
+			}
+			catch (CertificateException e)
+			{
+				throw new RuntimeException(FailedToInitCipher, e);
+			}
+			catch (UnrecoverableKeyException e)
+			{
+				throw new RuntimeException(FailedToInitCipher, e);
+			}
+			catch (IOException e)
+			{
+				throw new RuntimeException(FailedToInitCipher, e);
+			}
+			catch (NoSuchAlgorithmException e)
+			{
+				throw new RuntimeException(FailedToInitCipher, e);
+			}
+			catch (InvalidKeyException e)
+			{
+				throw new RuntimeException(FailedToInitCipher, e);
+			}
+		}
+
+
+		public string Decrypt(string encryted)
+		{
+			byte[] encryptedBytes = Base64.Decode(encryted, 0);
+			return System.Text.Encoding.UTF8.GetString(_cipher.DoFinal(encryptedBytes));
+		}
+
+		public string DecryptStored(string prefKey, Context context)
+		{
+			string enc = PreferenceManager.GetDefaultSharedPreferences(context).GetString(prefKey, null);
+
+			Toast.MakeText(context, "len="+Base64.Decode(enc, 0).Length.ToString(), ToastLength.Long).Show();
+			return Decrypt(enc);
+		}
+	}
+
+	public class FingerprintEncryption : FingerprintCrypt
+	{
+		
+		private KeyGenerator _keyGen;
+		
+
+		public FingerprintEncryption(FingerprintModule fingerprint, string keyId) : 
+			base(fingerprint, keyId)
+		{
+			_keyGen = fingerprint.KeyGenerator;
 			CreateKey();
 		}
 
+
 		/// <summary>
 		/// Creates a symmetric key in the Android Key Store which can only be used after the user 
 		/// has authenticated with fingerprint.
 		/// </summary>
 		private void CreateKey()
 		{
-			// The enrolling flow for fingerprint. This is where you ask the user to set up fingerprint
-			// for your flow. Use of keys is necessary if you need to know if the set of
-			// enrolled fingerprints has changed.
 			try
 			{
-				_fingerprint.Keystore.Load(null);
+				_keystore.Load(null);
-				// Set the alias of the entry in Android KeyStore where the key will appear
+				_keyGen.Init(new KeyGenParameterSpec.Builder(GetAlias(_keyId),
-				// and the constrains (purposes) in the constructor of the Builder
-				_fingerprint.KeyGenerator.Init(new KeyGenParameterSpec.Builder(GetAlias(_keyId),
 					KeyStorePurpose.Encrypt | KeyStorePurpose.Decrypt)
 					.SetBlockModes(KeyProperties.BlockModeCbc)
 					// Require the user to authenticate with a fingerprint to authorize every use
@@ -164,7 +322,7 @@ namespace keepass2android
 					.SetUserAuthenticationRequired(true)
 					.SetEncryptionPaddings(KeyProperties.EncryptionPaddingPkcs7)
 					.Build());
-				_fingerprint.KeyGenerator.GenerateKey();
+				_keyGen.GenerateKey();
 			}
 			catch (NoSuchAlgorithmException e)
 			{
@@ -184,13 +342,14 @@ namespace keepass2android
 			}
 		}
 
-		public bool InitCipher()
+		public override bool InitCipher()
 		{
 			try
 			{
-				_fingerprint.Keystore.Load(null);
+				_keystore.Load(null);
-				var key = _fingerprint.Keystore.GetKey(GetAlias(_keyId), null);
+				var key = _keystore.GetKey(GetAlias(_keyId), null);
 				_cipher.Init(CipherMode.EncryptMode, key);
+
 				_cryptoObject = new FingerprintManager.CryptoObject(_cipher);
 				return true;
 			}
@@ -200,69 +359,28 @@ namespace keepass2android
 			}
 			catch (KeyStoreException e)
 			{
-				throw new RuntimeException("Failed to init Cipher", e);
+				throw new RuntimeException(FailedToInitCipher, e);
 			}
 			catch (CertificateException e)
 			{
-				throw new RuntimeException("Failed to init Cipher", e);
+				throw new RuntimeException(FailedToInitCipher, e);
 			}
 			catch (UnrecoverableKeyException e)
 			{
-				throw new RuntimeException("Failed to init Cipher", e);
+				throw new RuntimeException(FailedToInitCipher, e);
 			}
 			catch (IOException e)
 			{
-				throw new RuntimeException("Failed to init Cipher", e);
+				throw new RuntimeException(FailedToInitCipher, e);
 			}
 			catch (NoSuchAlgorithmException e)
 			{
-				throw new RuntimeException("Failed to init Cipher", e);
+				throw new RuntimeException(FailedToInitCipher, e);
 			}
 			catch (InvalidKeyException e)
 			{
-				throw new RuntimeException("Failed to init Cipher", e);
+				throw new RuntimeException(FailedToInitCipher, e);
 			}
 		}
-
-		private string GetAlias(string keyId)
-		{
-			return "keepass2android." + keyId;
-		}
-
-		public bool IsFingerprintAuthAvailable
-		{
-			get
-			{
-				return _fingerprint.FingerprintManager.IsHardwareDetected
-					&& _fingerprint.FingerprintManager.HasEnrolledFingerprints;
-			}
-		}
-
-		public void StartListening(FingerprintManager.AuthenticationCallback callback)
-		{
-			if (!IsFingerprintAuthAvailable)
-				return;
-
-			_cancellationSignal = new CancellationSignal();
-			_selfCancelled = false;
-			_callback = callback;
-			_fingerprint.FingerprintManager.Authenticate(_cryptoObject, _cancellationSignal, 0 /* flags */, this, null);
-			
-		}
-
-		public void StopListening()
-		{
-			if (_cancellationSignal != null)
-			{
-				_selfCancelled = true;
-				_cancellationSignal.Cancel();
-				_cancellationSignal = null;
-			}
-		}
-
-		public void Encrypt(string textToEncrypt)
-		{
-			_cipher.DoFinal(MemUtil)
-		}
 	}
 }

src/FingerprintTest/FingerprintTest.csproj

@@ -81,7 +81,7 @@
   <ItemGroup>
     <XamarinComponentReference Include="xamandroidsupportv7appcompat">
       <Visible>False</Visible>
-      <Version>21.0.3.0</Version>
+      <Version>22.2.0.0</Version>
     </XamarinComponentReference>
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />

src/FingerprintTest/FingerprintTest.csproj.bak

@@ -47,14 +47,22 @@
     <Reference Include="System.Core" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Xml" />
+    <Reference Include="Xamarin.Android.Support.v4">
+      <HintPath>..\packages\Xamarin.Android.Support.v4.23.1.1.0\lib\MonoAndroid403\Xamarin.Android.Support.v4.dll</HintPath>
+    </Reference>
+    <Reference Include="Xamarin.Android.Support.v7.AppCompat">
+      <HintPath>..\packages\Xamarin.Android.Support.v7.AppCompat.23.1.1.0\lib\MonoAndroid403\Xamarin.Android.Support.v7.AppCompat.dll</HintPath>
+    </Reference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="FingerprintModule.cs" />
     <Compile Include="MainActivity.cs" />
     <Compile Include="Resources\Resource.Designer.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="GettingStarted.Xamarin" />
+    <None Include="packages.config" />
     <None Include="Resources\AboutResources.txt" />
     <None Include="Assets\AboutAssets.txt" />
   </ItemGroup>
@@ -70,6 +78,12 @@
   <ItemGroup>
     <None Include="Properties\AndroidManifest.xml" />
   </ItemGroup>
+  <ItemGroup>
+    <XamarinComponentReference Include="xamandroidsupportv7appcompat">
+      <Visible>False</Visible>
+      <Version>21.0.3.0</Version>
+    </XamarinComponentReference>
+  </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
      Other similar extension points exist, see Microsoft.Common.targets.

src/FingerprintTest/MainActivity.cs

@@ -14,10 +14,11 @@ using keepass2android;
 
 namespace FingerprintTest
 {
-	[Activity(Label = "FingerprintTest", MainLauncher = true, Icon = "@drawable/icon")]
+	[Activity(Label = "FingerprintTest", MainLauncher = true, Icon = "@drawable/icon", Theme = "@style/Theme.AppCompat")]
 	public class MainActivity : AppCompatActivity
 	{
 		int count = 1;
+		private string _keyId = "mykeyid";
 		const int FINGERPRINT_PERMISSION_REQUEST_CODE = 0;
 
 		protected override void OnCreate(Bundle bundle)
@@ -32,26 +33,61 @@ namespace FingerprintTest
 			Button button = FindViewById<Button>(Resource.Id.MyButton);
 			button.Visibility = ViewStates.Gone;
 			
-
 			RequestPermissions(new[] { Manifest.Permission.UseFingerprint }, FINGERPRINT_PERMISSION_REQUEST_CODE);
 		}
+		string prefKey = "enc_pref_key";
 
 		public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Permission[] grantResults)
 		{
 			if (requestCode == FINGERPRINT_PERMISSION_REQUEST_CODE && grantResults[0] == Android.Content.PM.Permission.Granted)
 			{
-				Button button = FindViewById<Button>(Resource.Id.MyButton);
+				Button encButton = FindViewById<Button>(Resource.Id.MyButton);
-				button.Visibility = ViewStates.Visible;
+				Button decButton = FindViewById<Button>(Resource.Id.Decrypt);
-				button.Enabled = true;
+				encButton.Visibility = ViewStates.Visible;
+				encButton.Enabled = true;
 				var fingerprint = new keepass2android.FingerprintModule(this);
 
-				button.Click += (sender, args) =>
+				encButton.Click += (sender, args) =>
 				{
+					
+					var fingerprintEnc = new FingerprintEncryption(fingerprint, _keyId);
+
+
+					if (fingerprintEnc.InitCipher())
+					{
+						fingerprintEnc.StartListening(new EncryptionCallback(this, fingerprintEnc, prefKey));
+
+
+					}
+					else
+					{
+						Toast.MakeText(this, "Error initiating cipher", ToastLength.Long).Show();
+					}
 
 				};
+
+				decButton.Click += (sender, args) =>
+				{
+					
+					var fingerprintDec = new FingerprintDecryption(fingerprint, _keyId, this, prefKey);
+
+
+					if (fingerprintDec.InitCipher())
+					{
+						fingerprintDec.StartListening(new DecryptionCallback(this, fingerprintDec,prefKey));
+
+
+					}
+					else
+					{
+						Toast.MakeText(this, "Error initiating cipher", ToastLength.Long).Show();
+					}
+
+				};
+
 				if (!fingerprint.KeyguardManager.IsKeyguardSecure)
 				{
-					button.Enabled = false;
+					encButton.Enabled = false;
 					// Show a message that the user hasn't set up a fingerprint or lock screen.
 					Toast.MakeText(this, "Secure lock screen hasn't set up.\n"
 						+ "Go to 'Settings -> Security -> Fingerprint' to set up a fingerprint", ToastLength.Long).Show();
@@ -61,45 +97,55 @@ namespace FingerprintTest
 
 				if (!fingerprint.FingerprintManager.HasEnrolledFingerprints)
 				{
-					button.Enabled = false;
+					encButton.Enabled = false;
 					// This happens when no fingerprints are registered.
 					Toast.MakeText(this, "Go to 'Settings -> Security -> Fingerprint' " +
 						"and register at least one fingerprint", ToastLength.Long).Show();
 					return;
 				}
-				var fingerprintEnc = new FingerprintEncryptionModule(fingerprint, "abc");
-
-				
-					if (fingerprintEnc.InitCipher())
-					{
-						fingerprintEnc.StartListening(new EncryptionCallback(this, fingerprintEnc));
-						
-						
-					}
-					else
-					{
-						Toast.MakeText(this, "Error initiating cipher", ToastLength.Long).Show();
-					}
 				
 			}
 		}
 	}
 
-	public class EncryptionCallback : FingerprintManager.AuthenticationCallback
+	public class DecryptionCallback : FingerprintManager.AuthenticationCallback
 	{
-		private readonly FingerprintEncryptionModule _fingerprintEnc;
+		private readonly Context _context;
+		private readonly FingerprintDecryption _fingerprintDec;
+		private readonly string _prefKey;
 
-		public EncryptionCallback(Context context, FingerprintEncryptionModule fingerprintEnc)
+		public DecryptionCallback(Context context, FingerprintDecryption fingerprintDec, string prefKey)
 		{
-			_fingerprintEnc = fingerprintEnc;
+			_context = context;
+			_fingerprintDec = fingerprintDec;
+			_prefKey = prefKey;
 		}
 
 		public override void OnAuthenticationSucceeded(FingerprintManager.AuthenticationResult result)
 		{
-			_fingerprintEnc.Encrypt("abc");
+			var prefs = PreferenceManager.GetDefaultSharedPreferences(Application.Context);
-			var edit = PreferenceManager.GetDefaultSharedPreferences(Application.Context).Edit();
+			Toast.MakeText(_context, _fingerprintDec.DecryptStored(_prefKey, _context), ToastLength.Long).Show();
-			edit.PutString("encrypted", );
 		}
 	}
+
+	public class EncryptionCallback : FingerprintManager.AuthenticationCallback
+	{
+		private readonly FingerprintCrypt _fingerprintEnc;
+		private readonly string _prefKey;
+
+		public EncryptionCallback(Context context, FingerprintCrypt fingerprintEnc, string prefKey)
+		{
+			_fingerprintEnc = fingerprintEnc;
+			_prefKey = prefKey;
+		}
+
+		public override void OnAuthenticationSucceeded(FingerprintManager.AuthenticationResult result)
+		{
+			
+			_fingerprintEnc.StoreEncrypted("some töst data", _prefKey, Application.Context);
+		}
+
+		
+	}
 }
 

src/FingerprintTest/Properties/AndroidManifest.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="FingerprintTest.FingerprintTest" android:versionCode="1" android:versionName="1.0">
 	<uses-sdk android:targetSdkVersion="15" />
+  <uses-permission android:name="android.permission.USE_FINGERPRINT" />
 	<application android:label="FingerprintTest" android:icon="@drawable/Icon"></application>
 </manifest>

src/FingerprintTest/Resources/layout/Main.axml

@@ -2,12 +2,15 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
-    android:layout_height="fill_parent"
+    android:layout_height="fill_parent">
-    >
+    <Button
-<Button  
+        android:id="@+id/MyButton"
-    android:id="@+id/MyButton"
+        android:layout_width="fill_parent"
-    android:layout_width="fill_parent" 
+        android:layout_height="wrap_content"
-    android:layout_height="wrap_content" 
+        android:text="@string/Hello" />
-    android:text="@string/Hello"
+    <Button
-    />
+        android:id="@+id/Decrypt"
-</LinearLayout>
+        android:layout_width="fill_parent"
+        android:layout_height="wrap_content"
+        android:text="Decrypt" />
+</LinearLayout>