Example of HeadSpin's HSFingerprintManager usage

DemoFingerprintActivity.java

/*-
 * #%L
 * Demo Fingerprint Authentication Activity
 * %%
 * Copyright (C) 2019 Headspin Inc.
 * %%
 * #L%
 */
package com.nextunicorn.app;

import android.annotation.TargetApi;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.os.CancellationSignal;
import android.content.Context;
import android.app.KeyguardManager;
import android.hardware.fingerprint.FingerprintManager;
import android.hardware.fingerprint.FingerprintManager.*;
import android.support.v4.app.ActivityCompat;
import android.widget.Toast;
import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.security.keystore.KeyProperties;
import java.security.KeyStore;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import javax.crypto.KeyGenerator;
import android.security.keystore.KeyGenParameterSpec;
import java.security.cert.CertificateException;
import java.security.InvalidAlgorithmParameterException;
import java.io.IOException;
import android.security.keystore.KeyPermanentlyInvalidatedException;
import android.support.annotation.RequiresApi;
import android.util.Log;
import java.security.InvalidKeyException;
import java.security.KeyStoreException;
import java.security.UnrecoverableKeyException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.Cipher;

// Import from HeadSpin biometrics library
import io.headspin.instruments.fingerprint.HSFingerprintManager;
import io.headspin.instruments.fingerprint.HSFingerprintAuthCallback;

@TargetApi(28)
@RequiresApi(23)
class DemoFingerprintActivity extends AppCompatActivity {

    private static String TAG = "DemoFingerprintActivity";
  
    private static String  KEY_NAME = "hot_key";
  
    private HSFingerprintManager  hsFingerprintManager;

    private KeyguardManager keyguardManager;
  
    private KeyStore keyStore;
  
    private KeyGenerator keyGenerator;
  
    private Cipher cipher;
  
    private CryptoObject cryptoObject;
  
    private CancellationSignal cancellationSignal;

    /**
     * Inherit [HSFingerprintAuthCallback] to get default toast messages or
     * or [android.hardware.fingerprint.FingerprintManager.AuthenticationCallback]
     * to implement your own callbacks.
     */
    private HSFingerprintCallback authCallback = new HSFingerprintAuthCallback() {
        @Override
        void onAuthenticationSucceeded(AuthenticationResult result) {
            super.onAuthenticationSucceeded(result);
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    finish();
                }
            }, 2000);
        }
    };

    @Override
    void onCreate(Bundle savedInstanceState) {

        Log.i(TAG, "creating DemoFingerprintActivity")

        super.onCreate(savedInstanceState);

        hsfingerprintManager = new HSFingerprintManager(this);

        setContentView(R.layout.activity_fingerprint);

        if (managersReady()) {
            generateKey();
            if (initCipher()) {
                cryptoObject = new CryptoObject(cipher);
                cancellationSignal = new CancellationSignal();

                if (hsFingerprintManager.ready()) {
                    /*
                    * authenticate() sends authCallback to the underlying HSfingerprintService
                    * so it can be called by Headspin biometrics API.
                    */
                    hsFingerprintManager.authenticate(cryptoObject, cancellationSignal,
                                                                    0, authCallback, null);
                }
            }
        }
    }

    @Override
    void onStop() {
        super.onStop();
        // IMPORTANT: call close() to stop the HSFingerprintService.
        hsFingerprintManager.close();
    }

    /*
     * This is a sample and thus using CBC Block mode should be good enough.
     * However, please take care to implement a more secure key for your app.
     */
    private boolean initCipher() {
        try {
            cipher = Cipher.getInstance(
                    KeyProperties.KEY_ALGORITHM_AES + "/"
                        + KeyProperties.BLOCK_MODE_CBC + "/"
                        + KeyProperties.ENCRYPTION_PADDING_PKCS7);
        } catch (NoSuchAlgorithmException e) {
            throw RuntimeException("Failed to get Cipher", e);
        } catch (NoSuchPaddingException e) {
            throw RuntimeException("Failed to get Cipher", e);
        }

        try {
            if (keyStore != null) {
                keyStore.load(null);
                SecretKey key = (SecretKey) keyStore.getKey(KEY_NAME, null);
                cipher.init(Cipher.ENCRYPT_MODE, key);
                return true;
            }
        } catch (KeyPermanentlyInvalidatedException e) {
            return false;
        } catch (KeyStoreException e) {
            throw RuntimeException("Failed to init Cipher", e);
        } catch (CertificateException e) {
            throw RuntimeException("Failed to init Cipher", e);
        } catch (UnrecoverableKeyException e) {
            throw RuntimeException("Failed to init Cipher", e);
        } catch (IOException e) {
            throw RuntimeException("Failed to init Cipher", e);
        } catch (NoSuchAlgorithmException e) {
            throw RuntimeException("Failed to init Cipher", e)
        } catch (InvalidKeyException e) {
            throw RuntimeException("Failed to init Cipher", e)
        }
    }

    private void generateKey() {
        try {
            keyStore = KeyStore.getInstance("AndroidKeyStore");
        } catch (Exception e) {
            e.printStackTrace();
        }

        try {
            keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES,
                                                    "AndroidKeyStore");
        } catch (NoSuchAlgorithmException e) {
            throw RuntimeException("Failed to get KeyGenerator instance", e);

        } catch (NoSuchProviderException e) {
            throw RuntimeException("Failed to get KeyGenerator instance", e);
        }

        try {
            if (keyStore != null) {
                keyStore.load(null);
                keyGenerator.init(KeyGenParameterSpec.Builder(
                    KEY_NAME,
                    KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT
                ).setBlockModes(KeyProperties.BLOCK_MODE_CBC)
                 .setUserAuthenticationRequired(true)
                 .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
                 .build());

                 keyGenerator.generateKey();
            }
        } catch (NoSuchAlgorithmException e ) {
            throw RuntimeException(e);
        } catch (InvalidAlgorithmParameterException e) {
            throw RuntimeException(e);
        } catch (CertificateException e) {
            throw RuntimeException(e);
        } catch (IOException e) {
            throw RuntimeException(e);
        }
    }

    private Boolean managersReady() {
        KeyguardManager keyguardManager = (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);

        /*
         * HSFingerprintManager fashions a ready() method that takes care of
         * inquiring the wrapped FingerprintManager's readiness.
         */
        if ((keyguardManager == null) || (!hsfingerprintManager.ready())) {
            return false;
        }

        if (keyguardManager.isKeyguardSecure == false) {
            Toast.makeText(this,
                "Lock screen security is not enabled in Settings",
                Toast.LENGTH_LONG).show();
            return false;
        }

        if (ActivityCompat.checkSelfPermission(this,
                        Manifest.permission.USE_FINGERPRINT) !=
                            PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this,
                    "Fingerprint authentication permission not enabled",
                    Toast.LENGTH_LONG).show();
            return false;
        }

        if (hsfingerprintManager?.hasEnrolledFingerprints() == false) {
            Toast.makeText(this,
                    "Register at least one fingerprint in Settings",
                    Toast.LENGTH_LONG).show();
            return false;
        }
        return true;
    }
}