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在通过指纹认证活动和处理程序后,如何使用加密对象(密钥)在android中加密?

fingerprint encryption authentication android

Aswin Darma Saputra · 技术社区 · 7 年前

private KeyStore keyStore;
// Variable used for storing the key in the Android Keystore container
private static final String KEY_NAME = "androidHive";
private Cipher cipher;
private TextView textView;

@TargetApi(Build.VERSION_CODES.M)
protected void generateKey() {
    try {
        keyStore = KeyStore.getInstance("AndroidKeyStore");
    } catch (Exception e) {
        e.printStackTrace();
    }

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

    try {
        keyStore.load(null);
        keyGenerator.init(new
                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 |
            InvalidAlgorithmParameterException
            | CertificateException | IOException e) {
        throw new RuntimeException(e);
    }
}

@TargetApi(Build.VERSION_CODES.M)
public boolean cipherInit() {
    try {
        cipher = Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/" + KeyProperties.BLOCK_MODE_CBC + "/" + KeyProperties.ENCRYPTION_PADDING_PKCS7);
    } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
        throw new RuntimeException("Failed to get Cipher", e);
    }

    try {
        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 | CertificateException | UnrecoverableKeyException | IOException | NoSuchAlgorithmException | InvalidKeyException e) {
        throw new RuntimeException("Failed to init Cipher", e);
    }
}

在指纹活动中的指纹验证码之后,该函数被这样调用

generateKey();

if (cipherInit()) {
    FingerprintManager.CryptoObject cryptoObject = new FingerprintManager.CryptoObject(cipher);
    FingerprintHandler helper = new FingerprintHandler(this);
    helper.startAuth(fingerprintManager, cryptoObject);
}

private Context context;

// Constructor
public FingerprintHandler(Context mContext) {
    context = mContext;
}

public void startAuth(FingerprintManager manager, FingerprintManager.CryptoObject cryptoObject) {
    CancellationSignal cancellationSignal = new CancellationSignal();
    if (ActivityCompat.checkSelfPermission(context, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {
        return;
    }
    manager.authenticate(cryptoObject, cancellationSignal, 0, this, null);
}

@Override
public void onAuthenticationError(int errMsgId, CharSequence errString) {
    this.update("Fingerprint Authentication error\n" + errString);
}

@Override
public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {
    this.update("Fingerprint Authentication help\n" + helpString);
}

@Override
public void onAuthenticationFailed() {
    this.update("Fingerprint Authentication failed.");
}

@Override
public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
    ((Activity) context).finish();
    Intent intent = new Intent(context, HomeActivity.class);
    context.startActivity(intent);
}

private void update(String e){
    TextView textView = (TextView) ((Activity)context).findViewById(R.id.errorText);
    textView.setText(e);
}

在认证成功将活动定向到HomeActivity之后,我想用HomeActivity中已经生成的密钥和之前已经初始化的Chipper加密一些东西,但我不知道如何调用之前已经生成的密钥和Chipper,举个例子,在指纹认证之后如何进行加密?这是我在大学的最后一个项目,所以我非常感谢任何能回答这个问题的人

1 回复 | 直到 7 年前

Omar Aflak 7 年前

一旦在密钥库中生成了密钥,就相当容易了。您只需要使用相同的初始化向量(IV)来加密和解密。

// encryption
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] ivBytes = cipher.getIV();
String dataToEncrypt = "Super secret data";
byte[] data = dataToEncrypt.getBytes();
byte[] encryptedData = cipher.doFinal(data);

// decryption
cipher.init(Cipher.DECRYPT_MODE, key, ivBytes);
byte[] decryptedData = cipher.doFinal(encryptedData);
String originalData = new String(decryptedData);

编辑:

我不确定您是否可以通过活动传递密码,但可以肯定地从任何活动中检索密钥库中的密钥。您只需要用于生成密钥的密钥名:

SecretKey cipherKey = (SecretKey) keyStore.getKey("keyName", null);

重要提示: