Question

我正在尝试设置BiometricPrompt，但是我需要使用CryptoObject进行身份验证，当https://developer.android.com/reference/android/hardware/biometrics/BiometricPrompt.Builder.html#setDeviceCredentialAllowed(boolean)设置为true时，这似乎是不可能的。

try {
      KeyGeneratorUtil.generateKeyPair("1", null);
    } catch (Exception e) {
      e.printStackTrace();
    }

    PrivateKey privateKey;
    try {
      privateKey = KeyGeneratorUtil.getPrivateKeyReference("test");
    } catch (Exception e) {
      return;
    }

    final Signature signature;
    try {
      signature = initSignature(privateKey);
    } catch (Exception e) {
      return;
    }
final BiometricPrompt.CryptoObject cryptoObject = new BiometricPrompt.CryptoObject(signature);

final BiometricPrompt biometricPrompt = new BiometricPrompt.Builder(context)
        .setTitle("Title")
        .setDescription("Description")
        .setDeviceCredentialAllowed(true)
        .build();

...

biometricPrompt.authenticate(cryptoObject, new CancellationSignal(), executor, callback);

运行此命令时，出现以下异常。

2019-07-03 13:50:45.140 13715-13715/kcvetano.com.biometricpromptpoc E/AndroidRuntime: FATAL EXCEPTION: main
    Process: kcvetano.com.biometricpromptpoc, PID: 13715
    java.lang.IllegalArgumentException: Device credential not supported with crypto
        at android.hardware.biometrics.BiometricPrompt.authenticate(BiometricPrompt.java:556)
        at kcvetano.com.biometricpromptpoc.BiometryAPI29.handleBiometry(BiometryAPI29.java:65)
        at kcvetano.com.biometricpromptpoc.MainActivity$1.onClick(MainActivity.java:56)
        at android.view.View.performClick(View.java:7251)
        at android.view.View.performClickInternal(View.java:7228)
        at android.view.View.access$3500(View.java:802)
        at android.view.View$PerformClick.run(View.java:27843)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7116)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:925)

Answer 1

以上答案在解决方案和解释方面都不太准确。

要同时使用生物特征认证和设备凭据以及加密对象，请执行以下步骤：

使用setUserAuthenticationRequired(true)和setUserAuthenticationValidityDurationSeconds(x)创建一个秘密密钥。

private SecretKey createSecretKey(String keyName ){
  KeyGenParameterSpec.Builder paramsBuilder = new KeyGenParameterSpec.Builder(keyName,
                    KeyProperties.PURPOSE_SIGN);
            paramsBuilder.setUserAuthenticationRequired(true);
            paramsBuilder.setUserAuthenticationValidityDurationSeconds(5);
            KeyGenParameterSpec keyGenParams = paramsBuilder.build();
            KeyGenerator keyGenerator = null;
           keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_HMAC_SHA256,
                        ANDROID_KEYSTORE);

            keyGenerator.init(keyGenParams);
            return keyGenerator.generateKey();
       }// All exceptions unhandled

初始化加密对象

Mac mac=Mac.getInstance("HmacSHA256");
SecretKey secretKey = getOrCreateSecretKey(keyName);
mac.init(secretKey);

3。对setDeviceCredentialAllowed(true)使用生物特征认证。不要在验证方法中传递加密对象参数-像这样-biometricPrompt.authenticate(promptInfo)

在onAuthentication成功下

public void onAuthenticationSucceeded(
                    @NonNull BiometricPrompt.AuthenticationResult result) {
                super.onAuthenticationSucceeded(result);
                byte[] bytes = "secret-text".getBytes();
                byte[] macResult = mac.doFinal(bytes);
                Log.d("hashed data--",bytesToHex(macResult));
            }

只有在设备解锁时间不超过x秒之前，mac对象才能工作。（setUserAuthenticationValidityDurationSeconds(x)）。

您可以在解锁设备x秒钟后尝试在onAuthSucceeded方法外使用mac对象。请注意，即使解锁手机，Mac对象也可以使用x秒钟。不必在应用程序内部将其解锁。

此处的更多信息：https://mobile-security.gitbook.io/mobile-security-testing-guide/android-testing-guide/0x05f-testing-local-authentication

Answer 2

这应该可以解决问题：

biometricPrompt.authenticate(null, new CancellationSignal(), executor, callback);

错误消息中或多或少都写有（可能会说 hidden ）：使用setDeviceCredentialAllowed(true)时不要使用加密对象。

这一切都取决于如何配置CryptoObject中用于加密操作的私钥。

我假设您用于初始化签名对象的私钥是使用setUserAuthenticationRequired(true)构建的。使用该选项构建的密钥只能用于一个加密操作。此外，还必须使用BiometricPrompt.authenticate或FingerprintManager.authenticate（现已不推荐使用BiometricPrompt）使用生物识别技术将其解锁。

official documentation讨论两种模式，如果仅在用户通过身份验证后才授权使用密钥，即：

使用setUserAuthenticationRequired(true)（现在为FingerprintManager.authenticate）解锁用BiometricPrompt.authenticate建造的钥匙
使用setUserAuthenticationValidityDurationSeconds流程创建的密钥必须通过KeyguardManager.createConfirmDeviceCredentialIntent流来解锁

official biometric auth training guide末尾的注释建议使用KeyguardManager.createConfirmDeviceCredentialIntent从BiometricPrompt流程切换到新的setDeviceCredentialAllowed(true)。

但是，这并不像将密钥的UserAuthenticationValidityDuration设置为非零值那样简单，因为这将在初始化签名对象后立即触发UserNotAuthenticatedException调用中的initSignature(privateKey)。还有更多警告...请参见下面的两个示例

生物特征密钥验证

fun biometric_auth() {

    val myKeyStore = KeyStore.getInstance("AndroidKeyStore")
    myKeyStore.load(null)

    val keyGenerator = KeyPairGenerator.getInstance(
        KeyProperties.KEY_ALGORITHM_EC,
        "AndroidKeyStore"
    )

    // build MY_BIOMETRIC_KEY
    val keyAlias = "MY_BIOMETRIC_KEY"
    val keyProperties = KeyProperties.PURPOSE_SIGN or KeyProperties.PURPOSE_VERIFY
    val builder = KeyGenParameterSpec.Builder(keyAlias, keyProperties)
        .setAlgorithmParameterSpec(ECGenParameterSpec("secp256r1"))
        .setDigests(KeyProperties.DIGEST_SHA256)
        .setUserAuthenticationRequired(true)


    keyGenerator.run {
        initialize(builder.build())
        generateKeyPair()
    }

    val biometricKeyEntry: KeyStore.Entry = myKeyStore.getEntry(keyAlias, null)
    if (biometricKeyEntry !is KeyStore.PrivateKeyEntry) {
        return
    }

    // create signature object
    val signature = Signature.getInstance("SHA256withECDSA")
    // init signature else "IllegalStateException: Crypto primitive not initialized" is thrown
    signature.initSign(biometricKeyEntry.privateKey)
    val cryptoObject = BiometricPrompt.CryptoObject(signature)

    // create biometric prompt
    // NOTE: using androidx.biometric.BiometricPrompt here
    val prompt = BiometricPrompt(
        this,
        AsyncTask.THREAD_POOL_EXECUTOR,
        object : BiometricPrompt.AuthenticationCallback() {
            // override the required methods...
            override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
                super.onAuthenticationError(errorCode, errString)
                Log.w(TAG, "onAuthenticationError $errorCode $errString")
            }

            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
                super.onAuthenticationSucceeded(result)
                Log.d(TAG, "onAuthenticationSucceeded" + result.cryptoObject)
                val sigBytes = signature.run {
                    update("hello world".toByteArray())
                    sign()
                }
                Log.d(TAG, "sigStr " + Base64.encodeToString(sigBytes, 0))
            }

            override fun onAuthenticationFailed() {
                super.onAuthenticationFailed()
                Log.w(TAG, "onAuthenticationFailed")
            }
        })
    val promptInfo = BiometricPrompt.PromptInfo.Builder()
        .setTitle("Unlock your device")
        .setSubtitle("Please authenticate to ...")
        // negative button option required for biometric auth
        .setNegativeButtonText("Cancel")
        .build()
    prompt.authenticate(promptInfo, cryptoObject)
}

PIN /密码/图案验证

fun password_auth() {

    val myKeyStore = KeyStore.getInstance("AndroidKeyStore")
    myKeyStore.load(null)

    val keyGenerator = KeyPairGenerator.getInstance(
        KeyProperties.KEY_ALGORITHM_EC,
        "AndroidKeyStore"
    )

    // build MY_PIN_PASSWORD_PATTERN_KEY
    val keyAlias = "MY_PIN_PASSWORD_PATTERN_KEY"
    val keyProperties = KeyProperties.PURPOSE_SIGN or KeyProperties.PURPOSE_VERIFY
    val builder = KeyGenParameterSpec.Builder(keyAlias, keyProperties)
        .setAlgorithmParameterSpec(ECGenParameterSpec("secp256r1"))
        .setDigests(KeyProperties.DIGEST_SHA256)
        // this would trigger an UserNotAuthenticatedException: User not authenticated when using the fingerprint
        // .setUserAuthenticationRequired(true)
        .setUserAuthenticationValidityDurationSeconds(10)


    keyGenerator.run {
        initialize(builder.build())
        generateKeyPair()
    }

    val keyEntry: KeyStore.Entry = myKeyStore.getEntry(keyAlias, null)
    if (keyEntry !is KeyStore.PrivateKeyEntry) {
        return
    }

    // create signature object
    val signature = Signature.getInstance("SHA256withECDSA")
    // this would fail with UserNotAuthenticatedException: User not authenticated
    // signature.initSign(keyEntry.privateKey)

    // create biometric prompt
    // NOTE: using androidx.biometric.BiometricPrompt here
    val prompt = BiometricPrompt(
        this,
        AsyncTask.THREAD_POOL_EXECUTOR,
        object : BiometricPrompt.AuthenticationCallback() {
            // override the required methods...
            override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
                super.onAuthenticationError(errorCode, errString)
                Log.w(TAG, "onAuthenticationError $errorCode $errString")
            }

            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
                super.onAuthenticationSucceeded(result)
                Log.d(TAG, "onAuthenticationSucceeded " + result.cryptoObject)
                // now it's safe to init the signature using the password key
                signature.initSign(keyEntry.privateKey)
                val sigBytes = signature.run {
                    update("hello password/pin/pattern".toByteArray())
                    sign()
                }
                Log.d(TAG, "sigStr " + Base64.encodeToString(sigBytes, 0))
            }

            override fun onAuthenticationFailed() {
                super.onAuthenticationFailed()
                Log.w(TAG, "onAuthenticationFailed")
            }
        })
    val promptInfo = BiometricPrompt.PromptInfo.Builder()
        .setTitle("Unlock your device")
        .setDeviceCredentialAllowed(true)
        .build()
    prompt.authenticate(promptInfo)
}

java.lang.IllegalArgumentException：加密不支持设备凭证

2 个答案: