Android指纹识别

原文:Android指纹识别

上一篇讲了通过FingerprintManager验证手机是否支持指纹识别,以及是否录入了指纹,这里进行指纹的验证.

//获取FingerprintManager实例

FingerprintManager mFingerprintManager =

                                                (FingerprintManager) context.getSystemService(Context.FINGERPRINT_SERVICE);

//执行验证监听

mFingerprintManager

                .authenticate(cryptoObject, mCancellationSignal, 0, this, null);

参数说明:

cryptoObject//FingerprintManager支持的加密对象的包装类。目前该框架支持Signature，Cipher和Mac对象。

mCancellationSignal//提供取消正在进行的操作的功能。

callback(参数中的this)//指纹识别的回调函数

cryptoObject初始化:

private KeyguardManager mKeyguardManager;

private FingerprintManager mFingerprintManager;

private static final String DIALOG_FRAGMENT_TAG = "myFragment";

private static final String SECRET_MESSAGE = "Very secret message";

public static boolean isAuthenticating = false;

public static final String PARAM_DISMISS_DIALOG = "param_dismiss_dialog";

/**

 * Alias for our key in the Android Key Store

 */

private static final String KEY_NAME = "my_key";

private KeyStore mKeyStore;

private KeyGenerator mKeyGenerator;

private Cipher mCipher;

@TargetApi(Build.VERSION_CODES.M)

private boolean initCipher() {

    try {

        mCipher = Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/"

                + KeyProperties.BLOCK_MODE_CBC + "/"

                + KeyProperties.ENCRYPTION_PADDING_PKCS7);

    } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {

        throw new RuntimeException("Failed to get an instance of Cipher", e);

    }

    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);

    }

}

/**

 * Creates a symmetric key in the Android Key Store which can only be used after the user has

 * authenticated with fingerprint.

 */

@TargetApi(Build.VERSION_CODES.M)

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.

    mKeyStore = null;

    mKeyGenerator = null;

    try {

        mKeyStore = KeyStore.getInstance("AndroidKeyStore");

    } catch (KeyStoreException e) {

        throw new RuntimeException("Failed to get an instance of KeyStore", e);

    }

    try {

        mKeyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");

    } catch (NoSuchAlgorithmException | NoSuchProviderException e) {

        throw new RuntimeException("Failed to get an instance of KeyGenerator", e);

    }

    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);

    }

}

FingerprintManager.CryptoObject cryptoObject = new FingerprintManager.CryptoObject(mCipher);

回调函数:

@Override

public void onAuthenticationError(int errMsgId, CharSequence errString) {

    //验证出现错误了

    //errString为错误的信息

}

@Override

public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {

    showError(helpString);

    //验证出现一些问题的系统提示,比如:请按久一点等提示信息.

}

@Override

public void onAuthenticationFailed() {

    showError("指纹验证失败");

    //在验证失败和出现问题以后,系统会继续执行监听,使用者需要在这里修改相关提示信息

}

@Override

public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {

    //验证成功

}