package authentication.fingerprint.android.jssec.org.fingerprintauthentication;

import android.app.AlertDialog;
import android.hardware.fingerprint.FingerprintManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Base64;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;

public class MainActivity extends AppCompatActivity {

    private FingerprintAuthentication mFingerprintAuthentication;
    private static final String SENSITIVE_DATA = "sensitive data";
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mFingerprintAuthentication = new FingerprintAuthentication(this);
        Button button_fingerprint_auth = (Button) findViewById(R.text.button_fingerprint_auth);
        button_fingerprint_auth.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                if (!mFingerprintAuthentication.isAuthenticating()) {
                    if (authenticateByFingerprint()) {
                        showEncryptedData(null);
                        setAuthenticationState(true);
                    }
                } else {
                    mFingerprintAuthentication.cancel();
                }
            }
        });
    }
    
    private boolean authenticateByFingerprint() {
        if (!mFingerprintAuthentication.isFingerprintHardwareDetected()) {
            // Terminal is not equipped with a fingerprint sensor
            return false;
        }
        if (!mFingerprintAuthentication.isFingerprintAuthAvailable()) {
            // *** POINT 3 *** Notify users that fingerprint registration will be required to create a key
            new AlertDialog.Builder(this)
                .setTitle(R.string.app_name)
                .setMessage("No fingerprint information has been registered.¥n" +
                    "Click ¥"Security¥" on the Settings menu to register fingerprints. ¥n" +
                    "Registering fingerprints allows easy authentication.")
                .setPositiveButton("OK", null)
                .show();
            return false;
        }
        // Callback that receives the results of fingerprint authentication
        FingerprintManager.AuthenticationCallback callback = new FingerprintManager.AuthenticationCallback() {
        
            @Override
            public void onAuthenticationError(int errorCode, CharSequence errString) {
                showMessage(errString, R.color.colorError);
                reset();
            }
            
            @Override
            public void onAuthenticationHelp(int helpCode, CharSequence helpString) {
                showMessage(helpString, R.color.colorHelp);
            }
            
            @Override
            public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
                Cipher cipher = result.getCryptoObject().getCipher();
                try {
                    // *** POINT 7*** Restrict encrypted data to items that can be restored (replaced) by methods other than fingerprint authentication
                    byte[]

encrypted = cipher.doFinal(SENSITIVE_DATA.getBytes());
showEncryptedData(encrypted);
} catch (IllegalBlockSizeException | BadPaddingException e) {
}
showMessage(getString(R.string.fingerprint_auth_succeeded), R.color.colorAuthenticated);
reset();
}

@Override
public void onAuthenticationFailed() {
    showMessage(getString(R.string.fingerprint_auth_failed), R.color.colorError);
}
};
if (mFingerprintAuthentication.startAuthentication(callback)) {
    showMessage(getString(R.string.fingerprint_processing), R.color.colorNormal);
    return true;
}
return false;
}

private void setAuthenticationState(boolean authenticating) {
    Button button = (Button) findViewById(R.id.button_fingerprint_auth);
    button.setText(authenticating ? R.string.cancel : R.string.authenticate);
}

private void showEncryptedData(byte[] encrypted) {
    TextView textView = (TextView) findViewById(R.id.encryptedData);
    if (encrypted != null) {
        textView.setText(Base64.encodeToString(encrypted, 0));
    } else {
        textView.setText("");
    }
}

private String getCurrentTimeString() {
    long currentTimeMillis = System.currentTimeMillis();
    Date date = new Date(currentTimeMillis);
    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("HH:mm:ss.SSS");
    return simpleDateFormat.format(date);
}

private void showMessage(CharSequence msg, int colorId) {
    TextView textView = (TextView) findViewById(R.id.textView);
    textView.setText(getCurrentTimeString() + " :¥n" + msg);
    textView.setTextColor(getResources().getColor(colorId, null));
}

private void reset() {
    setAuthenticationState(false);
}

package authentication.fingerprint.android.jssec.org.fingerprintauthentication;

import android.app.KeyguardManager;
import android.content.Context;
import android.hardware.fingerprint.FingerprintManager;
import android.os.CancellationSignal;
import android.security.keystore.KeyGenParameterSpec;
import android.security.keystore.KeyInfo;
import android.security.keystore.KeyPermanentlyInvalidatedException;
import android.security.keystore.KeyProperties;
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.NoSuchProviderException;
import java.security.UnrecoverableKeyException;
import java.security.cert.CertificateException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;

public class FingerprintAuthentication {

    private static final String KEY_NAME = "KeyForFingerprintAuthentication";
    private static final String PROVIDER_NAME = "AndroidKeyStore";
    private KeyguardManager mKeyguardManager;
    private FingerprintManager mFingerprintManager;
    private CancellationSignal mCancellationSignal;
    private KeyStore mKeyStore;
    private KeyGenerator mKeyGenerator;
    private Cipher mCipher;

    public FingerprintAuthentication(Context context) {
        mKeyguardManager = (KeyguardManager) context.getSystemService(Context.KEYGUARD_SERVICE);
        mFingerprintManager = (FingerprintManager) context.getSystemService(Context.FINGERPRINT_SERVICE
        );
        reset();
    }

    public boolean startAuthentication(final FingerprintManager.AuthenticationCallback callback) {
        if (!generateAndStoreKey())
            return false;
        if (!initializeCipherObject())
            return false;
        FingerprintManager.CryptoObject cryptoObject = new
``` ```
new RuntimeException("failed to generate a key", e);
    }
}

private boolean initializeCipherObject() {
    try {
        mKeyStore.load(null);
        SecretKey key = (SecretKey) mKeyStore.getKey(KEY_NAME, null);
        SecretKeyFactory factory = SecretKeyFactory.getInstance(KeyProperties.KEY_ALGORITHM_AES, PROVIDER_NAME);
        KeyInfo info = (KeyInfo) factory.getKeySpec(key, KeyInfo.class);
        mCipher.init(Cipher.ENCRYPT_MODE, key);
        return true;
    } catch (KeyPermanentlyInvalidatedException e) {
        // *** POINT 6 *** Design your app on the assumption that the status of fingerprint registration will change between when keys are created and when keys are used
        return false;
    } catch (KeyStoreException | CertificateException 
        | UnrecoverableKeyException | IOException
        | NoSuchAlgorithmException | InvalidKeySpecException 
        | NoSuchProviderException | InvalidKeyException e) {
        throw new RuntimeException("failed to init Cipher", e);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="authentication.fingerprint.android.jssec.org.fingerprintauthentication" >
    <!-- +++ POINT 1 *** Declare the use of the USE_FINGERPRINT permission -->
    <uses-permission android:name="android.permission.USE_FINGERPRINT" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:screenOrientation="portrait" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

if (!mFingerprintAuthentication.isFingerprintAuthAvailable()) {
    // **Point** Notify users that fingerprint registration will be required to create a key
    new AlertDialog.Builder(this)
        .setTitle(R.string.app_name)
        .setMessage("No fingerprint information has been registered.¥n" +
            " Click ¥"Security¥" on the Settings menu to register fingerprints.¥n" +
            " Registering fingerprints allows easy authentication.")
        .setPositiveButton("OK", null)
        .show();
    return false;
}

try {
    // Obtain an instance from the "AndroidKeyStore" Provider
    KeyGenerator keyGenerator =
``` Чтобы связать информацию об отпечатках пальцев и существующий ключ, используйте элемент KeyStore для регистрации этого ключа в уже настроенных элементах, чтобы активировать запросы аутентификации пользователя.

Связывание информации об отпечатках пальцев с существующим ключом:  
```java
SecretKey key = …; // существующий ключ
KeyStore keyStore = KeyStore.getInstance(«AndroidKeyStore»);
keyStore.load(null);
keyStore.setEntry(
    "alias_for_the_key",
    new KeyStore.SecretKeyEntry(key),
    new KeyProtection.Builder(KeyProperties.PURPOSE_ENCRYPT)
        .setUserAuthenticationRequired(true) // Включить запросы на аутентификацию пользователя (отпечаток пальца)
    .build());