Question

need help to build a fingerprint app that we have sslserversocket to tell a file use finger print before open the file

what have been done below

Here is my mainactivity.java and fingerprintHandler.java below

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/heading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:padding="20dp"
        android:text="Fingerprint Authentication"
        android:textAlignment="center"
        android:textColor="@android:color/black"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0" />

    <TextView
        android:id="@+id/paraMessage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        android:text="Place your finger on the fingerprint scanner to proceed"
        android:textAlignment="center"
        android:textColor="@color/colorAccent"
        android:textSize="16sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/fingerprint_image_view"
        app:layout_constraintVertical_bias="0.178" />

    <ImageView
        android:id="@+id/fingerprint_image_view"
        android:layout_width="110dp"
        android:layout_height="119dp"
        app:srcCompat="@drawable/fingerprint_icon"
        tools:layout_editor_absoluteX="137dp"
        tools:layout_editor_absoluteY="90dp" />
</android.support.constraint.ConstraintLayout>

....................................................
package com.believe.securefolder;

import android.Manifest;

import android.app.KeyguardManager;

import android.content.pm.PackageManager;

import android.hardware.fingerprint.FingerprintManager;

import android.os.Build;

import android.support.v4.content.ContextCompat;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.widget.ImageView;

import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView heading, paraMesaage;

    private ImageView fingerPrintImageView;

    private FingerprintManager fingerprintManager;

    private KeyguardManager keyguardManager;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        heading = (TextView) findViewById(R.id.heading);

        paraMesaage = (TextView) findViewById(R.id.paraMessage);

        fingerPrintImageView = (ImageView) findViewById(R.id.fingerprint_image_view);

        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)

        {

            fingerprintManager = (FingerprintManager) getSystemService(FINGERPRINT_SERVICE);

            keyguardManager = (KeyguardManager) getSystemService(KEYGUARD_SERVICE);

            // Add 

            // this line to AndroidManifest.xml file

            if(!fingerprintManager.isHardwareDetected())

            {

                paraMesaage.setText("Fingerprint Scanner not detected in your device!");

            }

            else if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.USE_FINGERPRINT)

                    != PackageManager.PERMISSION_GRANTED)

            {

                paraMesaage.setText("Permission not granted to use Fingerprint Scanner!");

            }

            else if(!keyguardManager.isKeyguardSecure())

            {

                paraMesaage.setText("Add lock to your device in Device Settings!");

            }

            else if(!fingerprintManager.hasEnrolledFingerprints())

            {

                paraMesaage.setText("You should add at least 1 fingerprint to use this feature!");

            }

            else

            {

                paraMesaage.setText("Place your finger on the fingerprint scanner to proceed");

                FingerprintHandler fingerprintHandler = new FingerprintHandler(MainActivity.this);

                fingerprintHandler.startAuth(fingerprintManager, null);

            }

        }

   }

}

--------------------------------------------------------------

package com.believe.securefolder;

import android.annotation.TargetApi;

import android.app.Activity;

import android.content.Context;

import android.hardware.fingerprint.FingerprintManager;

import android.os.Build;

import android.os.CancellationSignal;

import android.support.v4.content.ContextCompat;

import android.widget.ImageView;

import android.widget.TextView;

import static com.believe.securefolder.R.drawable.*;

@TargetApi(Build.VERSION_CODES.M)

public class FingerprintHandler extends FingerprintManager.AuthenticationCallback {

    private Context context;

    private int done_icon;

    public FingerprintHandler(Context context)

    {

        this.context = context;

    }

    public void startAuth(FingerprintManager fingerprintManager, FingerprintManager.CryptoObject cryptoObject)

    {

        CancellationSignal cancellationSignal = new CancellationSignal();

        fingerprintManager.authenticate(cryptoObject, cancellationSignal, 0, this, null);

    }

    @Override

    public void onAuthenticationError(int errorCode, CharSequence errString) {

        this.update("There was an auth error: " + errString, false);

    }

    @Override

    public void onAuthenticationFailed() {

        this.update("Authentication failed!", false);

    }

    @Override

    public void onAuthenticationHelp(int helpCode, CharSequence helpString) {

        this.update("Error: " + helpString, false);

    }

    @Override

    public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {

        this.update("You can now access the app!", true);

    }

    public void update(String s, boolean b)

    {

        TextView paraMessage = (TextView) ((Activity) context).findViewById(R.id.paraMessage);

        ImageView fingerPrintImageView = (ImageView) ((Activity) context).findViewById(R.id.fingerprint_image_view);

        paraMessage.setText(s);

        if(b == false)

        {

            paraMessage.setTextColor(ContextCompat.getColor(context, R.color.colorPrimary));

        }

        else

        {

            paraMessage.setTextColor(ContextCompat.getColor(context, R.color.colorAccent));

            fingerPrintImageView.setImageResource(done_icon);

        }

    }

}

Answer 1

To Implement Android biometric authentication

the main activity code can be implemented as:

import androidx.appcompat.app.AppCompatActivity;
import androidx.biometric.BiometricPrompt;
import android.os.Bundle;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import androidx.fragment.app.FragmentActivity;
import android.util.Log;
import android.view.View;

import androidx.annotation.NonNull;

public class MainActivity extends AppCompatActivity {

   private static final String TAG = MainActivity.class.getName();

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main)

/Create a thread pool with a single thread//

       Executor newExecutor = Executors.newSingleThreadExecutor();

       FragmentActivity activity = this;

//Start listening for authentication events//

       final BiometricPrompt myBiometricPrompt = new BiometricPrompt(activity, newExecutor, new BiometricPrompt.AuthenticationCallback() {
           @Override

//onAuthenticationError is called when a fatal error occurrs//

           public void onAuthenticationError(int errorCode, @NonNull CharSequence errString) {
               super.onAuthenticationError(errorCode, errString);
               if (errorCode == BiometricPrompt.ERROR_NEGATIVE_BUTTON) {
               } else {

//Print a message to Logcat//

                   Log.d(TAG, "An unrecoverable error occurred");
               }
           }

//onAuthenticationSucceeded is called when a fingerprint is matched successfully//

 @Override
           public void onAuthenticationSucceeded(@NonNull BiometricPrompt.AuthenticationResult result) {
               super.onAuthenticationSucceeded(result);

//Print a message to Logcat//

               Log.d(TAG, "Fingerprint recognised successfully");
           }

//onAuthenticationFailed is called when the fingerprint doesn’t match//

           @Override
           public void onAuthenticationFailed() {
               super.onAuthenticationFailed();

//Print a message to Logcat//

               Log.d(TAG, "Fingerprint not recognised");
           }
       });

//Create the BiometricPrompt instance//

       final BiometricPrompt.PromptInfo promptInfo = new BiometricPrompt.PromptInfo.Builder()

//Add some text to the dialog//

               .setTitle("Title text goes here")
               .setSubtitle("Subtitle goes here")
               .setDescription("This is the description")
               .setNegativeButtonText("Cancel")

//Build the dialog//

.build();

//Assign an onClickListener to the app’s “Authentication” button//

       findViewById(R.id.launchAuthentication).setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               myBiometricPrompt.authenticate(promptInfo);
           }
       });

   }

Certificate pinning is the solution to this problem. It means hard-coding the certificate known to be used by the server in the mobile application. The app can then ignore the device’s trust store and rely on its own, and allow only SSL connections to hosts signed with certificates stored inside the application.

This also gives a possibility of trusting a host with a self-signed certificate without the need to install additional certificates on the device.

There are three important steps in the process:

• obtain a certificate for the desired host (preferably the whole certificate chain)
• make sure the certificate is in .bks format - this step is crucial in order for pinning to work properly across all devices
• use Apache HTTP client shipped with Android - initialize it to use the obtained .bks keystore for SSL connections

To obtain a .pem certificate for a site.

• oneway of doing this through command line tool                                                    openssl s_client -showcerts -connect api.host.com:443 </dev/null 2>/dev/null|openssl x509 -outform PEM >mycertfile.pem

converting it to .bks keystore

following is the command:

keytool -importcert -v -trustcacerts -file "mycertfile.pem" -alias ca -keystore "keystore.bks" -provider org.bouncycastle.jce.provider.BouncyCastleProvider -providerpath "bcprov-ext-jdk15on-1.46.jar" -storetype BKS -storepass testing

Pinning the certificate to DefaultHttpClient

Using trial and error it has been established that only .bks keystores can be used for certificate pinning. Keystore file must be placed in res/raw folder.

The following code snippet demonstrates loading a keystore:

InputStream in = resources.openRawResource(certificateRawResource);

keyStore = KeyStore.getInstance("BKS");
keyStore.load(resourceStream, password);

to create a new instance of DefaultHttpClient we can use HttpClientBuilder class:

DefaultHttpClient httpClient = new HttpClientBuilder()
  .setConnectionTimeout(10000) //timeout until a connection is etablished in ms; zero means no timeout
  .setSocketTimeout(60000) //timeout for waiting for data in ms (socket timeout); zero means no timeout
  .setHttpPort(80) //sets the port for HTTP connections, default is 80
  .setHttpsPort(443) //sets the port for HTTPS connections, default is 443
  .setCookieStore(new BasicCookieStore()) //assigns a cookie store, BasicCookieStore is assigned by default
  .pinCertificates(getResources(), R.raw.keystore, STORE_PASS) //pins the certificate from raw resources
  .build();