prebuilts/gradle/FingerprintDialog/Application/src/main/java/com/example/android/fingerprintdialog/MainActivity.java - platform/developers/build - Git at Google

 /*
  * Copyright (C) 2015 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License
  */

 package com.example.android.fingerprintdialog;

 import android.Manifest;
 import android.app.Activity;
 import android.app.KeyguardManager;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.hardware.fingerprint.FingerprintManager;
 import android.os.Bundle;
 import android.security.keystore.KeyGenParameterSpec;
 import android.security.keystore.KeyPermanentlyInvalidatedException;
 import android.security.keystore.KeyProperties;
 import android.util.Base64;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.Button;
 import android.widget.TextView;
 import android.widget.Toast;

 import java.io.IOException;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.KeyStore;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
 import java.security.UnrecoverableKeyException;
 import java.security.cert.CertificateException;

 import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
 import javax.crypto.IllegalBlockSizeException;
 import javax.crypto.KeyGenerator;
 import javax.crypto.SecretKey;
 import javax.inject.Inject;

 /**
  * Main entry point for the sample, showing a backpack and "Purchase" button.
  */
 public class MainActivity extends Activity {

     private static final String TAG = MainActivity.class.getSimpleName();

     private static final String DIALOG_FRAGMENT_TAG = "myFragment";
     private static final String SECRET_MESSAGE = "Very secret message";
     /** Alias for our key in the Android Key Store */
     private static final String KEY_NAME = "my_key";

     private static final int FINGERPRINT_PERMISSION_REQUEST_CODE = 0;

     @Inject KeyguardManager mKeyguardManager;
     @Inject FingerprintManager mFingerprintManager;
     @Inject FingerprintAuthenticationDialogFragment mFragment;
     @Inject KeyStore mKeyStore;
     @Inject KeyGenerator mKeyGenerator;
     @Inject Cipher mCipher;
     @Inject SharedPreferences mSharedPreferences;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         ((InjectedApplication) getApplication()).inject(this);

         requestPermissions(new String[]{Manifest.permission.USE_FINGERPRINT},
                 FINGERPRINT_PERMISSION_REQUEST_CODE);
     }

     @Override
     public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] state) {
         if (requestCode == FINGERPRINT_PERMISSION_REQUEST_CODE
                 && state[0] == PackageManager.PERMISSION_GRANTED) {
             setContentView(R.layout.activity_main);
             Button purchaseButton = (Button) findViewById(R.id.purchase_button);
             if (!mKeyguardManager.isKeyguardSecure()) {
                 // 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",
                         Toast.LENGTH_LONG).show();
                 purchaseButton.setEnabled(false);
                 return;
             }
             if (!mFingerprintManager.hasEnrolledFingerprints()) {
                 purchaseButton.setEnabled(false);
                 // This happens when no fingerprints are registered.
                 Toast.makeText(this,
                         "Go to 'Settings -> Security -> Fingerprint' and register at least one fingerprint",
                         Toast.LENGTH_LONG).show();
                 return;
             }
             createKey();
             purchaseButton.setEnabled(true);
             purchaseButton.setOnClickListener(new View.OnClickListener() {
                 @Override
                 public void onClick(View v) {
                     findViewById(R.id.confirmation_message).setVisibility(View.GONE);
                     findViewById(R.id.encrypted_message).setVisibility(View.GONE);

                     // Set up the crypto object for later. The object will be authenticated by use
                     // of the fingerprint.
                     if (initCipher()) {

                         // Show the fingerprint dialog. The user has the option to use the fingerprint with
                         // crypto, or you can fall back to using a server-side verified password.
                         mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
                         boolean useFingerprintPreference = mSharedPreferences
                                 .getBoolean(getString(R.string.use_fingerprint_to_authenticate_key),
                                         true);
                         if (useFingerprintPreference) {
                             mFragment.setStage(
                                     FingerprintAuthenticationDialogFragment.Stage.FINGERPRINT);
                         } else {
                             mFragment.setStage(
                                     FingerprintAuthenticationDialogFragment.Stage.PASSWORD);
                         }
                         mFragment.show(getFragmentManager(), DIALOG_FRAGMENT_TAG);
                     } else {
                         // This happens if the lock screen has been disabled or or a fingerprint got
                         // enrolled. Thus show the dialog to authenticate with their password first
                         // and ask the user if they want to authenticate with fingerprints in the
                         // future
                         mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
                         mFragment.setStage(
                                 FingerprintAuthenticationDialogFragment.Stage.NEW_FINGERPRINT_ENROLLED);
                         mFragment.show(getFragmentManager(), DIALOG_FRAGMENT_TAG);
                     }
                 }
             });
         }
     }

     /**
      * Initialize the {@link Cipher} instance with the created key in the {@link #createKey()}
      * method.
      *
      * @return {@code true} if initialization is successful, {@code false} if the lock screen has
      * been disabled or reset after the key was generated, or if a fingerprint got enrolled after
      * the key was generated.
      */
     private boolean initCipher() {
         try {
             mKeyStore.load(null);
             SecretKey key = (SecretKey) mKeyStore.getKey(KEY_NAME, null);
             mCipher.init(Cipher.ENCRYPT_MODE, key);
             return true;
         } catch (KeyPermanentlyInvalidatedException e) {
             return false;
         } catch (KeyStoreException | CertificateException | UnrecoverableKeyException | IOException
                 | NoSuchAlgorithmException | InvalidKeyException e) {
             throw new RuntimeException("Failed to init Cipher", e);
         }
     }

     public void onPurchased(boolean withFingerprint) {
         if (withFingerprint) {
             // If the user has authenticated with fingerprint, verify that using cryptography and
             // then show the confirmation message.
             tryEncrypt();
         } else {
             // Authentication happened with backup password. Just show the confirmation message.
             showConfirmation(null);
         }
     }

     // Show confirmation, if fingerprint was used show crypto information.
     private void showConfirmation(byte[] encrypted) {
         findViewById(R.id.confirmation_message).setVisibility(View.VISIBLE);
         if (encrypted != null) {
             TextView v = (TextView) findViewById(R.id.encrypted_message);
             v.setVisibility(View.VISIBLE);
             v.setText(Base64.encodeToString(encrypted, 0 /* flags */));
         }
     }

     /**
      * Tries to encrypt some data with the generated key in {@link #createKey} which is
      * only works if the user has just authenticated via fingerprint.
      */
     private void tryEncrypt() {
         try {
             byte[] encrypted = mCipher.doFinal(SECRET_MESSAGE.getBytes());
             showConfirmation(encrypted);
         } catch (BadPaddingException | IllegalBlockSizeException e) {
             Toast.makeText(this, "Failed to encrypt the data with the generated key. "
                     + "Retry the purchase", Toast.LENGTH_LONG).show();
             Log.e(TAG, "Failed to encrypt the data with the generated key." + e.getMessage());
         }
     }

     /**
      * Creates a symmetric key in the Android Key Store which can only be used after the user has
      * authenticated with fingerprint.
      */
     public 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 {
             mKeyStore.load(null);
             // Set the alias of the entry in Android KeyStore where the key will appear
             // and the constrains (purposes) in the constructor of the Builder
             mKeyGenerator.init(new KeyGenParameterSpec.Builder(KEY_NAME,
                     KeyProperties.PURPOSE_ENCRYPT |
                             KeyProperties.PURPOSE_DECRYPT)
                     .setBlockModes(KeyProperties.BLOCK_MODE_CBC)
                             // Require the user to authenticate with a fingerprint to authorize every use
                             // of the key
                     .setUserAuthenticationRequired(true)
                     .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
                     .build());
             mKeyGenerator.generateKey();
         } catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException
                 | CertificateException | IOException e) {
             throw new RuntimeException(e);
         }
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         getMenuInflater().inflate(R.menu.menu_main, menu);
         return true;
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         int id = item.getItemId();

         if (id == R.id.action_settings) {
             Intent intent = new Intent(this, SettingsActivity.class);
             startActivity(intent);
             return true;
         }
         return super.onOptionsItemSelected(item);
     }
 }
	/*
	* Copyright (C) 2015 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License
	*/

	package com.example.android.fingerprintdialog;

	import android.Manifest;
	import android.app.Activity;
	import android.app.KeyguardManager;
	import android.content.Intent;
	import android.content.SharedPreferences;
	import android.content.pm.PackageManager;
	import android.hardware.fingerprint.FingerprintManager;
	import android.os.Bundle;
	import android.security.keystore.KeyGenParameterSpec;
	import android.security.keystore.KeyPermanentlyInvalidatedException;
	import android.security.keystore.KeyProperties;
	import android.util.Base64;
	import android.util.Log;
	import android.view.Menu;
	import android.view.MenuItem;
	import android.view.View;
	import android.widget.Button;
	import android.widget.TextView;
	import android.widget.Toast;

	import java.io.IOException;
	import java.security.InvalidAlgorithmParameterException;
	import java.security.InvalidKeyException;
	import java.security.KeyStore;
	import java.security.KeyStoreException;
	import java.security.NoSuchAlgorithmException;
	import java.security.UnrecoverableKeyException;
	import java.security.cert.CertificateException;

	import javax.crypto.BadPaddingException;
	import javax.crypto.Cipher;
	import javax.crypto.IllegalBlockSizeException;
	import javax.crypto.KeyGenerator;
	import javax.crypto.SecretKey;
	import javax.inject.Inject;

	/**
	* Main entry point for the sample, showing a backpack and "Purchase" button.
	*/
	public class MainActivity extends Activity {

	private static final String TAG = MainActivity.class.getSimpleName();

	private static final String DIALOG_FRAGMENT_TAG = "myFragment";
	private static final String SECRET_MESSAGE = "Very secret message";
	/** Alias for our key in the Android Key Store */
	private static final String KEY_NAME = "my_key";

	private static final int FINGERPRINT_PERMISSION_REQUEST_CODE = 0;

	@Inject KeyguardManager mKeyguardManager;
	@Inject FingerprintManager mFingerprintManager;
	@Inject FingerprintAuthenticationDialogFragment mFragment;
	@Inject KeyStore mKeyStore;
	@Inject KeyGenerator mKeyGenerator;
	@Inject Cipher mCipher;
	@Inject SharedPreferences mSharedPreferences;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	((InjectedApplication) getApplication()).inject(this);

	requestPermissions(new String[]{Manifest.permission.USE_FINGERPRINT},
	FINGERPRINT_PERMISSION_REQUEST_CODE);
	}

	@Override
	public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] state) {
	if (requestCode == FINGERPRINT_PERMISSION_REQUEST_CODE
	&& state[0] == PackageManager.PERMISSION_GRANTED) {
	setContentView(R.layout.activity_main);
	Button purchaseButton = (Button) findViewById(R.id.purchase_button);
	if (!mKeyguardManager.isKeyguardSecure()) {
	// 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",
	Toast.LENGTH_LONG).show();
	purchaseButton.setEnabled(false);
	return;
	}
	if (!mFingerprintManager.hasEnrolledFingerprints()) {
	purchaseButton.setEnabled(false);
	// This happens when no fingerprints are registered.
	Toast.makeText(this,
	"Go to 'Settings -> Security -> Fingerprint' and register at least one fingerprint",
	Toast.LENGTH_LONG).show();
	return;
	}
	createKey();
	purchaseButton.setEnabled(true);
	purchaseButton.setOnClickListener(new View.OnClickListener() {
	@Override
	public void onClick(View v) {
	findViewById(R.id.confirmation_message).setVisibility(View.GONE);
	findViewById(R.id.encrypted_message).setVisibility(View.GONE);

	// Set up the crypto object for later. The object will be authenticated by use
	// of the fingerprint.
	if (initCipher()) {

	// Show the fingerprint dialog. The user has the option to use the fingerprint with
	// crypto, or you can fall back to using a server-side verified password.
	mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
	boolean useFingerprintPreference = mSharedPreferences
	.getBoolean(getString(R.string.use_fingerprint_to_authenticate_key),
	true);
	if (useFingerprintPreference) {
	mFragment.setStage(
	FingerprintAuthenticationDialogFragment.Stage.FINGERPRINT);
	} else {
	mFragment.setStage(
	FingerprintAuthenticationDialogFragment.Stage.PASSWORD);
	}
	mFragment.show(getFragmentManager(), DIALOG_FRAGMENT_TAG);
	} else {
	// This happens if the lock screen has been disabled or or a fingerprint got
	// enrolled. Thus show the dialog to authenticate with their password first
	// and ask the user if they want to authenticate with fingerprints in the
	// future
	mFragment.setCryptoObject(new FingerprintManager.CryptoObject(mCipher));
	mFragment.setStage(
	FingerprintAuthenticationDialogFragment.Stage.NEW_FINGERPRINT_ENROLLED);
	mFragment.show(getFragmentManager(), DIALOG_FRAGMENT_TAG);
	}
	}
	});
	}
	}

	/**
	* Initialize the {@link Cipher} instance with the created key in the {@link #createKey()}
	* method.
	*
	* @return {@code true} if initialization is successful, {@code false} if the lock screen has
	* been disabled or reset after the key was generated, or if a fingerprint got enrolled after
	* the key was generated.
	*/
	private boolean initCipher() {
	try {
	mKeyStore.load(null);
	SecretKey key = (SecretKey) mKeyStore.getKey(KEY_NAME, null);
	mCipher.init(Cipher.ENCRYPT_MODE, key);
	return true;
	} catch (KeyPermanentlyInvalidatedException e) {
	return false;
	} catch (KeyStoreException \| CertificateException \| UnrecoverableKeyException \| IOException
	\| NoSuchAlgorithmException \| InvalidKeyException e) {
	throw new RuntimeException("Failed to init Cipher", e);
	}
	}

	public void onPurchased(boolean withFingerprint) {
	if (withFingerprint) {
	// If the user has authenticated with fingerprint, verify that using cryptography and
	// then show the confirmation message.
	tryEncrypt();
	} else {
	// Authentication happened with backup password. Just show the confirmation message.
	showConfirmation(null);
	}
	}

	// Show confirmation, if fingerprint was used show crypto information.
	private void showConfirmation(byte[] encrypted) {
	findViewById(R.id.confirmation_message).setVisibility(View.VISIBLE);
	if (encrypted != null) {
	TextView v = (TextView) findViewById(R.id.encrypted_message);
	v.setVisibility(View.VISIBLE);
	v.setText(Base64.encodeToString(encrypted, 0 /* flags */));
	}
	}

	/**
	* Tries to encrypt some data with the generated key in {@link #createKey} which is
	* only works if the user has just authenticated via fingerprint.
	*/
	private void tryEncrypt() {
	try {
	byte[] encrypted = mCipher.doFinal(SECRET_MESSAGE.getBytes());
	showConfirmation(encrypted);
	} catch (BadPaddingException \| IllegalBlockSizeException e) {
	Toast.makeText(this, "Failed to encrypt the data with the generated key. "
	+ "Retry the purchase", Toast.LENGTH_LONG).show();
	Log.e(TAG, "Failed to encrypt the data with the generated key." + e.getMessage());
	}
	}

	/**
	* Creates a symmetric key in the Android Key Store which can only be used after the user has
	* authenticated with fingerprint.
	*/
	public 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 {
	mKeyStore.load(null);
	// Set the alias of the entry in Android KeyStore where the key will appear
	// and the constrains (purposes) in the constructor of the Builder
	mKeyGenerator.init(new KeyGenParameterSpec.Builder(KEY_NAME,
	KeyProperties.PURPOSE_ENCRYPT \|
	KeyProperties.PURPOSE_DECRYPT)
	.setBlockModes(KeyProperties.BLOCK_MODE_CBC)
	// Require the user to authenticate with a fingerprint to authorize every use
	// of the key
	.setUserAuthenticationRequired(true)
	.setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
	.build());
	mKeyGenerator.generateKey();
	} catch (NoSuchAlgorithmException \| InvalidAlgorithmParameterException
	\| CertificateException \| IOException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
	getMenuInflater().inflate(R.menu.menu_main, menu);
	return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
	int id = item.getItemId();

	if (id == R.id.action_settings) {
	Intent intent = new Intent(this, SettingsActivity.class);
	startActivity(intent);
	return true;
	}
	return super.onOptionsItemSelected(item);
	}
	}