Android指紋識别

原文: Android指紋識别 上一篇 講了通過 FingerprintManager 驗證手機是否支援指紋識别,以及是否錄入了指紋,這裡進行指紋的驗證.

//擷取FingerprintManager執行個體
FingerprintManager mFingerprintManager =
                                                (FingerprintManager) context.getSystemService(Context.FINGERPRINT_SERVICE);
//執行驗證監聽
mFingerprintManager
                .authenticate(cryptoObject, mCancellationSignal, 0, this, null);           

參數說明:

cryptoObject//FingerprintManager支援的加密對象的包裝類。目前該架構支援Signature，Cipher和Mac對象。
mCancellationSignal//提供取消正在進行的操作的功能。
callback(參數中的this)//指紋識别的回調函數           

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);           

回調函數:

@Override
public void onAuthenticationError(int errMsgId, CharSequence errString) {
    //驗證出現錯誤了
    //errString為錯誤的資訊
}

@Override
public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {
    showError(helpString);
    //驗證出現一些問題的系統提示,比如:請按久一點等提示資訊.
}

@Override
public void onAuthenticationFailed() {
    showError("指紋驗證失敗");
    //在驗證失敗和出現問題以後,系統會繼續執行監聽,使用者需要在這裡修改相關提示資訊
}

@Override
public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
    //驗證成功
}