Android fingerprint on SDK<23 - android

I have a project on Android with minSDK=17 and targetSDK=23. We have a fingerprint authentication in this project made using FingerprintManager class (it was added in SDK23). We added SDK version check, so we are not using anything related to fingerprint if SDK<23. But in older SDK versions app behaviour is unpredictable: on some versions app just crashing, on other -- fingerprint not working (so, it's ok).
My question:
1) Is it any good and easy-to-implement libraries for minSDK=17, that can recognize fingerprints?
2) How can I avoid app crashing in devices with SDK<23?
Crash error:
E/dalvikvm: Could not find class 'android.hardware.fingerprint.FingerprintManager', referenced from method nl.intratuin.LoginActivity.loginByFingerprint
E/AndroidRuntime: FATAL EXCEPTION: main java.lang.VerifyError:
LoginActivity at java.lang.Class.newInstanceImpl(Native Method)
Some new info: created HelloWorld fingerprint project using this tutorial:
http://www.techotopia.com/index.php/An_Android_Fingerprint_Authentication_Tutorial
Found the root of the problem:
FingerprintDemoActivity->cipherInit:
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);
}
First catch block breacking whole app with error I mentioned above. Of course, I can just remove this catch (this exception extends InvalidKeyException, so it will be handled), and return false in case of any exceptions. Is it any better way?

I think, I found acceptable solution: catch not KeyPermanentlyInvalidatedException, but InvalidKeyException. Everything working fine this way. Still have no idea how this exception crashed whole app...

It happened to me also..even when i used : if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M).. my app crashes on android 4.4- kitkat. so eventually the problem was in the initCipher method in the catches part - see the following code (even though i m not suppose to get there as it targeted to M and above... very strange behaviour..) :
#TargetApi(Build.VERSION_CODES.M)
private boolean initCipher() {
try {
mKeyStore.load(null);
SecretKey key = (SecretKey) mKeyStore.getKey(KEY_NAME, null);
mCipher.init(Cipher.ENCRYPT_MODE, key);
return true;
} catch (KeyStoreException | CertificateException | UnrecoverableKeyException | IOException
| NoSuchAlgorithmException e) {
throw new RuntimeException("Failed to init Cipher", e);
} catch (InvalidKeyException e) {
e.printStackTrace();
return false;
}
}
apparently the order off the catches matter..so just make sure to write it as i mentioned.

Reason for Crash:
The FingerprintManager class works with Android version 23 and Higher.
If your app is using FingerprintManager class and runs on older version of Android then you will encounter this exception.
Supporting older versions of Android:
Use FingerprintManagerCompat instead of FingerprintManager if you are planning to support Android <23. The FingerprintManagerCompat class internally checks for the Android version and handle Authentication part with ease.
How to Use it:
Replace android.hardware.fingerprint.FingerprintManager With android.support.v4.hardware.fingerprint.FingerprintManagerCompat
Replace android.os.CancellationSignal With android.support.v4.os.CancellationSignal
See Sample Code
https://github.com/hiteshsahu/FingerPrint-Authentication-With-React-Native-Android/blob/master/android/app/src/main/java/com/aproject/view/Fragments/FingerprintAuthenticationDialogFragment.java

Have a look at a library created by afollestad called digitus.
This library can fall back to a password if fingerprints are not available.
Any devices prior to SDK 23 need to use their own separate device manufacturer based sdk.

just follow android studio hint, it will be OK.
try {
mKeyStore.load(null);
SecretKey key = (SecretKey) mKeyStore.getKey(keyName, null);
cipher.init(Cipher.ENCRYPT_MODE, key);
return true;
} catch (IOException | NoSuchAlgorithmException | CertificateException
| UnrecoverableKeyException | KeyStoreException | InvalidKeyException e) {
e.printStackTrace();
throw new RuntimeException("Failed to init Cipher", e);
}

To answer the second part of the question
How can I avoid app crashing in devices with SDK<23?
This simplistic logic check will suffice:
if (Build.VERSION.SDK_INT < 23) {
// Handle the mechanism where the SDK is older.
}else{
// Handle the mechanism where the SDK is 23 or later.
}

I solved this by moving all the fingerprint code to a helper class so that the classes related to the fingerprint code are not imported in the activity and by instantiating the helper class only when the SDK_INT is greater than 23 (In my case, as I'm supporting only Android 6+)

I also had this problem.Even when i used : if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M).. my app crashes on lower API's. I solved that as follow:
Replaced these codes:
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);
}
with:
try {
keyStore.load(null);
} catch (CertificateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
SecretKey key = null;
try {
key = (SecretKey) keyStore.getKey(KEY_NAME,
null);
} catch (KeyStoreException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (UnrecoverableKeyException e) {
e.printStackTrace();
}
try {
cipher.init(Cipher.ENCRYPT_MODE, key);
} catch (InvalidKeyException e) {
e.printStackTrace();
}
return true;

Related

decodeHex method not found on Device, but working on Emulator

I'm working on the project with RSA encryption, and need to use the method from Apache commons-codec, which is:
Hex.encodeHex(byte[])
Hex.decodeHex(String)
Both methods are working fine on Android emulator, but it will return NoSuchMethodError on Device
public String RSADecrypt(final String message) {
try {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, getPrivateKey());
byte[] decryptedBytes = cipher.doFinal(Hex.decodeHex(message));
return new String(decryptedBytes);
} catch (BadPaddingException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (DecoderException e) {
e.printStackTrace();
}
return "";
}
java.lang.NoSuchMethodError: No static method decodeHex(Ljava/lang/String;)[B in class Lorg/apache/commons/codec/binary/Hex; or its super classes (declaration of 'org.apache.commons.codec.binary.Hex' appears in /system/framework/org.apache.http.legacy.boot.jar)
My emulator run on Pie, Oreo, & Nougat
My device run on Nougat & Marshmallow
Some Android versions contain an older version of the Apache commons-codec library (1.3) where the decodeHex(String) method didn't yet exist. Try calling decodeHex(char[]) instead. I.e. modify your code like this:
byte[] decryptedBytes = cipher.doFinal(Hex.decodeHex(message.toCharArray()));
That should work with commons-codec v1.3.

Removal of Fingerprint not triggering InvalidKeyException for Fingerprnt Authentication

I am facing issue with Fingerprint authentication, actually, I have integrated Fingerprint Authentication in my app and working fine except one case.
I have set up two Fingerprint in my device, after initializing KeyGenerator with Fingerprint KEY, I have removed one Fingerprint from device and come back to my app and performing Fingerprint Auth it is working fine. I don't know why it is not triggering InvalidKeyException as like adding Fingerprint works. Is this expected behavior or any bug with OS?
Device Details are below,
Device : Pixel
OS: Android 8.0
Code of my implementation follows,
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);
}
}
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);
}
}
}
I have already tried with few posts(How to detect the removal fingerprint in Android?, Android Fingerprint API and Private/Public keys, Android Key Invalidation when Fingerprints removed), nothing helped me to get rid of it.
Your code is not strictly tied to fingerprints. All it has that is somewhat related is:
setUserAuthenticationRequired(true)
That says that the key that you are creating in the AndroidKeyStore requires user authentication. It does not say anything about fingerprints.
If the user has fingerprints registered, the user could use a fingerprint to authenticate for the purposes of using this key. That would be for any fingerprint registered by the user, and in your case, you still have a registered fingerprint (even after the user removed the second fingerprint). Also, the user does not have to use a fingerprint to authenticate — they could use their passphrase, PIN, or pattern, if they choose.
Is this expected behavior or any bug with OS?
This is expected behavior.

Android Fingerprint invalidation

I'm playing around with the Fingerprint demo for Android, in particular the invalidation scenarios, but need a little help to translate this into production worthy logic.
I've tested the app and get the initCipher to fail due to invalidation after adding a fingerprint, but the app has to be running and the key generated while you change the settings. This is because the demo generates a new key each time the app starts. In reality you wouldn't want to do this, but instead generate the key if doesn't exist and reuse it if it does to enforce proper invalidation whether the app is running or not.
How can you modify the app so that the key isn't generated each time, but instead a check to see if one exists first is performed, then that key loaded subsequently? Can you then remove the key once invalidated so the previous logic and enrolment cycle applies?
Found the answer on my own by looking at the KeyStore class a bit more and modifying initCipher(). Not the best implementation, but good enough to test out stuff:
private boolean initCipher(Cipher cipher, String keyName) {
try {
mKeyStore.load(null);
// ADDED: Check is keystore contains my key name
if(!mKeyStore.containsAlias(DEFAULT_KEY_NAME)) {
// ADDED: Create if it doesn't
createKey(DEFAULT_KEY_NAME, true);
}
SecretKey key = (SecretKey) mKeyStore.getKey(keyName, null);
cipher.init(Cipher.ENCRYPT_MODE, key);
return true;
} catch (KeyPermanentlyInvalidatedException e) {
// ADDED: Remove the key if it is invalidated so
// it can be created fresh next time
try {
mKeyStore.deleteEntry(keyName);
} catch (KeyStoreException e1) {
e1.printStackTrace();
return false;
}
return false;
} catch (KeyStoreException | CertificateException | UnrecoverableKeyException | IOException
| NoSuchAlgorithmException | InvalidKeyException e) {
throw new RuntimeException("Failed to init Cipher", e);
}
}
Also need to remove the createKey() call from onCreate() too obviously.

Issue with Robolectric with cipher in android application

Hi I am using Robolectric for test cases. I am facing some issue while simulating for encryption relateed test cases. I tried to use cipher with AES for encryption. And it is giving me some error. I tried it in following manner :
#Test
public void testGet() {
Cipher cipher = null;
try {
SecretKey sks= getKeySpec(pass, salt);
cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, sks);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (InvalidKeySpecException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
}
}
public SecretKey getKeySpec(char[] pass, byte[] salt) throws NoSuchAlgorithmException, InvalidKeySpecException {
//generate key spec...
return secretKeyFactory.generateSecret(keySpec);
}
It gives me following error :
Illegal key size or default parameters
I already added JCE for illegal size exception. It is working if I run it on device and properly working in my application. Only thing when I try with robolectric it is giving me this error.Need some help. Thank you.
The reason behind this is Robolectric runs on JVM. JVM supports up to 128 bit key encryption only. Therefore if you are using 256 bit key encryption you need to use Java Cryptography Extension (JCE). follow this answer to how to do that

How to Generate Key and Chiper initiation below Android API 23?

Am Using Fingerprint Authentication for App. Want to Support for below API 23 also. For that am Using FingerprintManagerCompat. I don't know how to Generate Key and Chiper initiation in Pre-Android API 23.
Below Code am Used for API 23 - Generate Key
protected void generateKey() {
try {
keyStore = KeyStore.getInstance("AndroidKeyStore");
} catch (Exception e) {
e.printStackTrace();
}
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);
}
}
Below Code am Used for API 23 - Chiper initiation
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 (KeyStoreException | CertificateException
| UnrecoverableKeyException | IOException
| NoSuchAlgorithmException | InvalidKeyException e) {
throw new RuntimeException("Failed to init Cipher", e);
}
}
I don't know how initiate these two things in Pre API 23 to access FingerprintManagerCompat, Help me to solve this issue.
FingerprintManager is not available in pre-marshmallow devices. They have added this API in Marshamallow which is specified here
No.You can't Generate Key and cipher below API 23(Marshmallow 6.0).
Some android device have fingerprint sensor below API 21 but android only supports for API 23 and above.You have to use their sdk for fingerprint authentication.Samsung provide their own sdk for fingerprint authentication i.e Pass Sdk.
You can see this link.Sample project for Finger Print Authentication here

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