安卓指纹对称加密及登录功能的实现，阿里 P8 大牛从零开始教 Android 开源框架

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对称加密的主要实现步骤如下：

1. 新建一个 KeyStore 密钥库，用于存放密钥；

2. 获取 KeyGenerator 密钥生成工具，生成密钥；

3. 通过密钥初始化 Cipher 对象，生成加密对象 CryptoObject；

4. 调用 authenticate() 方法启动指纹传感器并开始监听。

1.新建一个 KeyStore 密钥库存放密钥：

/**

• 创建 keystore

• @throws Exception*/public CryptoObjectHelper() throws Exception {KeyStore _keystore = KeyStore.getInstance(KEYSTORE_NAME);_keystore.load(null);}

2.获取 KeyGenerator 密钥生成工具，生成密钥:

/**

• 获取秘钥生成器，用于生成秘钥

• @throws Exception*/public void CreateKey() throws Exception {KeyGenerator keyGen = KeyGenerator.getInstance(KEY_ALGORITHM, KEYSTORE_NAME);KeyGenParameterSpec keyGenSpec =new KeyGenParameterSpec.Builder(KEY_NAME, KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT).setBlockModes(BLOCK_MODE).setEncryptionPaddings(ENCRYPTION_PADDING).setUserAuthenticationRequired(true).build();keyGen.init(keyGenSpec);keyGen.generateKey();}

3.通过密钥初始化 Cipher 对象，生成加密对象 CryptoObject：

/**

• @throws Exception

• 密码生成，递归实现*/Cipher createCipher(boolean retry) throws Exception {Key key = GetKey();Cipher cipher = Cipher.getInstance(TRANSFORMATION);try {cipher.init(Cipher.ENCRYPT_MODE | Cipher.DECRYPT_MODE, key);} catch (KeyPermanentlyInvalidatedException e) {_keystore.deleteEntry(KEY_NAME);//删除获取的码，保留生成的密码 if (retry) {createCipher(false);} else {throw new Exception("Could not create the cipher", e);}}return cipher;}

4.调用 authenticate() 方法启动指纹传感器并开始监听：

CryptoObjectHelper cryptoObjectHelper = new CryptoObjectHelper();if (cancellationSignal == null) {cancellationSignal = new CancellationSignal();}fingerprintManager.authenticate(cryptoObjectHelper.buildCryptoObject(), 0,cancellationSignal, myAuthCallback, null);

最后我们在回调的类中监听指纹识别的结果:

public class MyAuthCallback extends FingerprintManagerCompat.AuthenticationCallback {

private Handler handler = null;

public MyAuthCallback(Handler handler) {super();this.handler = handler;}

/**

• 验证错误信息*/@Overridepublic void onAuthenticationError(int errMsgId, CharSequence errString) {super.onAuthenticationError(errMsgId, errString);if (handler != null) {handler.obtainMessage(Constant.MSG_AUTH_ERROR, errMsgId, 0).sendToTarget();}}

/**

• 身份验证帮助*/@Overridepublic void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {super.onAuthenticationHelp(helpMsgId, helpString);if (handler != null) {handler.obtainMessage(Constant.MSG_AUTH_HELP, helpMsgId, 0).sendToTarget();}}

/**

• 验证成功*/@Overridepublic void onAuthenticationSucceeded(FingerprintManagerCompat.AuthenticationResult result) {super.onAuthenticationSucceeded(result);if (handler != null) {handler.obtainMessage(Constant.MSG_AUTH_SUCCESS).sendToTarget();}}

/**

• 验证失败*/@Overridepublic void onAuthenticationFailed() {super.onAuthenticationFailed();if (handler != null) {handler.obtainMessage(Constant.MSG_AUTH_FAILED).sendToTarget();}}}

好了，上面一直讲的是对称加密以实现指纹识别；

接下来写了一个使用指纹进行登录的 demo 及封装（这里没有使用加密..）：

我们先来看下我总结的指纹登录流程

指纹识别一定会有成功、失败等各种情况，所以先定义一个回调监听

/**

• Description: 指纹识别回调

• Created by jia on 2017/11/27.

• 人之所以能，是相信能*/public interface FingerListener {

/**

• 开始识别*/void onStartListening();

/**

• 停止识别*/void onStopListening();

/**

• 识别成功

• @param result*/void onSuccess(FingerprintManager.AuthenticationResult result);

/**

• 识别失败*/void onFail(boolean isNormal,String info);

/**

• 多次识别失败 的 回调方法

• @param errorCode

• @param errString*/void onAuthenticationError(int errorCode, CharSequence errString);

/**

• 识别提示*/void onAuthenticationHelp(int helpCode, CharSequence helpString);

}

1、先封装了指纹工具类

private FingerprintManager manager;private KeyguardManager mKeyManager;private CancellationSignal mCancellationSignal;//回调方法 private FingerprintManager.AuthenticationCallback mSelfCancelled;

private Context mContext;

private FingerListener listener;

指纹识别相关管理类当然是必须的了。

2、初始化它们

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {manager = (FingerprintManager) mContext.getSystemService(Context.FINGERPRI

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NT_SERVICE);mKeyManager = (KeyguardManager) mContext.getSystemService(Context.KEYGUARD_SERVICE);mCancellationSignal = new CancellationSignal();initSelfCancelled();}

3、初始化系统的识别回调

private void initSelfCancelled() {mSelfCancelled = new FingerprintManager.AuthenticationCallback() {@Overridepublic void onAuthenticationError(int errorCode, CharSequence errString) {// 多次指纹密码验证错误后，进入此方法；并且，不能短时间内调用指纹验证 listener.onAuthenticationError(errorCode, errString);}

@Overridepublic void onAuthenticationHelp(int helpCode, CharSequence helpString) {listener.onAuthenticationHelp(helpCode, helpString);}

@Overridepublic void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {listener.onSuccess(result);}

@Overridepublic void onAuthenticationFailed() {listener.onFail(true, "识别失败");}};}

4、开始识别

/**

• 开始监听识别*/public void startListening(FingerListener listener) {

this.listener = listener;