​
Installation

The Android SDK is a set of lightweight libraries. The libraries deliver as Android Archive Repository, .aar, files. The minimum supported version of Android is v7, level 24.

Prove manages a maven repository with Android binaries to enable integration with Gradle.

Update the dependencies object in the build.gradle file:

dependencies {
  // Existing dependencies are here.

  // Add the Prove Link dependencies:
  implementation 'com.prove.sdk:proveauth:6.4.1'
}

You’ll also need to point to the repository by updating your settings.gradle file with the Maven repository:

dependencyResolutionManagement {
    // Existing repository settings are here.

    repositories {
        // Existing repositories are here.

        // Add the Prove Link Maven repository:
        maven {
            url = "https://prove.jfrog.io/artifactory/libs-public-maven/"
        }
    }
}

The following needs added to the build.gradle file to also download dependency libraries:

dependencies {
  implementation fileTree('libs')
}

If you receive an error message on the application@fullBackupContent value, you can resolve it by adding this line of code to your application AndroidManifest.xml file inside the <application>...</application> node. Add it as an attribute to the opening application tag:

<application
...
tools:replace="android:fullBackupContent"
...>
</application>

​
Permissions

The Prove Auth SDK and its children SDKs merge the following permissions into the main application:

<!-- Required to perform authentication -->
<uses-permission android:name="android.permission.INTERNET" />

<!-- Required to access information about networks -->
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<!-- Required for ConnectivityManager.requestNetwork -->
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />

​
Send the Type of Flow: Mobile

Unlike the Web SDK, when using the Android SDK, use the mobile flow. Pass mobile to the Unify() function on the server. In a mobile flow, OTP validation is performed on the mobile phone.

In the mobile flow, once OTP validation is complete, the AuthFinishStep function executes.

​
Authenticate()

The SDK requires an authToken as a parameter for the Authenticate() function. This token returns from the Unify() call of the server SDK. The token is session specific, limiting it to a single flow. It also expires after 15 minutes.

​
Retrieve authToken

To start the flow, you’ll need to send a request to your backend server with possession type, and an optional phone number if using Prove’s possession check.

String initialize(String phoneNumber, String possessionType) {
    YourBackendClient backend = new YourBackendClient(); // Backend API client

    // TODO: Build your InitializeRequest object
    InitializeRequest initializeRequest = new InitializeRequest(phoneNumber, possessionType);

    // Send an initialize request to your backend server to get authToken
    InitializeResponse response = backend.initialize(initializeRequest);

    // TODO: define your own InitializeResponse object to parse authToken string
    return response.getAuthToken();
}

​
Setup Authenticator

Once you have the authToken, build the authenticator for the mobile flow.

Java
// Object implementing AuthFinishStep interface
AuthFinishStep authFinishStep = new AuthFinishStep() {
...
};

// Objects implementing OtpStartStep/OtpFinishStep interfaces
OtpStartStep otpStartStep = new OtpStartStep() {
...
};

OtpFinishStep otpFinishStep = new OtpFinishStep() {
...
};

ProveAuth proveAuth = ProveAuth.builder()
    .withAuthFinishStep(authId -> verify(authId)) // verify(authId) call defined in #Validate the Mobile Phone section
    .withOtpFallback(otpStartStep, otpFinishStep)
    .withContext(this)
    .build();

The cellular data connection can sometimes be unavailable during testing. The Builder class offers a withTestMode(boolean testMode) method, which permits simulated successful session results while connected to a Wi-Fi network only (without a cellular data connection available). Testing using a Wi-Fi connection is useful in the Sandbox environment.

Java
ProveAuth proveAuth = ProveAuth.builder()
    .withAuthFinishStep(authId -> verify(authId))
    .withOtpFallback(otpStartStep, otpFinishStep)
    .withContext(this)
    .withTestMode(true) // Test mode flag
    .build();

​
Performing the Authentication

The ProveAuth object is thread safe. You can use it as a singleton. Most Prove Auth methods are blocking and therefore can’t execute in the main application thread. The application employs an executor service with a minimum of two threads to manage threads due to the SDK’s ability to process concurrent blocking requests.

public class MyAuthenticator {
    private final MyBackendClient backend = new MyBackendClient(); // Backend API client

    private final AuthFinishStep authFinishStep = new AuthFinishStep() {
        @Override
        void execute(String authId) {
            try {
                AuthFinishResponse response = backend.authFinish("My App", authId);
                ... // Check the authentication status returned in the response
            } catch (IOException e) {
                String failureCause = e.getCause() != null ? e.getCause().getMessage() : "Failed to request authentication results";
                // Authentication failed due to request failure
            }
        }
    };

    private ProveAuth proveAuth;

    public MyAuthenticator(Context context) {
        proveAuth = ProveAuth.builder()
          .withAuthFinishStep(authFinishStep)
			    .withOtpFallback(otpStartStep, otpFinishStep)
          .withContext(context)
          .build();
    }

    public void authenticate() throws IOException, ProveAuthException {
        AuthStartResponse response = backend.authStart("My Prove Auth App");

        proveAuth.authenticate(response.getAuthToken());
    }
}

​
Validate the Mobile Phone

In the AuthFinishStep, you’ll specify a function to call once the possession checks are complete on the mobile phone. This endpoint on your back end server calls the Validate() function to check phone number validation. If it was successful, the server returns the results from the Challenge() function, including customer information.

// Send a verify request to get return customer information.
void verify(String: authId) {
  YourBackendClient backend = new YourBackendClient(); // Backend API client

  // Build your VerifyRequest object
  VerifyRequest verifyRequest = new VerifyRequest(authId, ...);

  // Send a verify request to your backend server to get return customer information.
  VerifyResponse response = backend.verify(verifyRequest);
}

​
OTP Configuration

You need to implement two functions for the one-time password (OTP) handling - a start and a finish step.

You can’t use retry functionality in OTP.

To set the OTP handlers, implement OtpStartStep and OtpFinishStep. The Java snippet has an example.

OtpStartStep example:

package com.prove.android_sample_app;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;

import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.ActivityResultRegistry;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.lifecycle.DefaultLifecycleObserver;
import androidx.lifecycle.LifecycleOwner;

import com.prove.sdk.proveauth.OtpStartInput;
import com.prove.sdk.proveauth.OtpStartStepCallback;
import com.prove.sdk.proveauth.PhoneNumberValidationException;
import com.prove.sdk.proveauth.ProveAuthException;

import java.util.concurrent.atomic.AtomicReference;

public class OtpStartStep implements
        com.prove.sdk.proveauth.OtpStartStep,
        DefaultLifecycleObserver {
    public static final String OTP_START_STEP_KEY = "OtpStartStep";
    private final ActivityResultRegistry registry;
    private ActivityResultLauncher<Intent> launcher;
    private final Context context;
    private final AtomicReference<OtpStartStepCallback> otpStartStepCallbackRef =
            new AtomicReference<>();

    public OtpStartStep(Context context, @NonNull ActivityResultRegistry registry) {
        this.context = context;
        this.registry = registry;
    }

    @Override
    public void execute(boolean phoneNumberNeeded, @Nullable ProveAuthException exception,
            OtpStartStepCallback otpStartStepCallback) {
        if (exception instanceof PhoneNumberValidationException) {
            otpStartStepCallbackRef.set(otpStartStepCallback);
            Intent intent = new Intent(context, OtpPhoneNumberInputActivity.class);
            intent.putExtra(IntentExtraFields.OTP_ERROR,
                    "Phone number is invalid, please try again.");
            launcher.launch(intent);
            return;
        }

        if (phoneNumberNeeded) {
            // We need to store callback object, it will be needed to complete this activity
            // by calling it with the results.
            otpStartStepCallbackRef.set(otpStartStepCallback);
            Intent intent = new Intent(context, OtpPhoneNumberInputActivity.class);
            launcher.launch(intent);
        } else {
            otpStartStepCallback.onSuccess(new OtpStartInput(""));
        }
    }

    public void onCreate(@NonNull LifecycleOwner owner) {
        launcher = registry.register(OTP_START_STEP_KEY, owner,
                new ActivityResultContracts.StartActivityForResult(),
                result -> {
                    OtpStartStepCallback callback = otpStartStepCallbackRef.get();
                    if (callback == null) {
                        return;
                    }

                    if (result.getResultCode() == Activity.RESULT_OK) {
                        Intent intent = result.getData();
                        if (intent != null) {
                            String phoneNumber = intent.getStringExtra(
                                    IntentExtraFields.OTP_PHONE_NUMBER_FIELD);
                            callback.onSuccess(new OtpStartInput(phoneNumber));
                        } else {
                            callback.onError();
                        }
                    } else {
                        callback.onError();
                    }
                });
    }
}

OtpFinishStep example:

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.ActivityResultRegistry;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.lifecycle.DefaultLifecycleObserver;
import androidx.lifecycle.LifecycleOwner;

import com.prove.sdk.proveauth.OtpFinishInput;
import com.prove.sdk.proveauth.OtpFinishStepCallback;
import com.prove.sdk.proveauth.OtpValidationException;
import com.prove.sdk.proveauth.ProveAuthException;

import java.util.concurrent.atomic.AtomicReference;

public class OtpFinishStep implements
        com.prove.sdk.proveauth.OtpFinishStep,
        DefaultLifecycleObserver {
    public static final String OTP_FINISH_STEP_KEY = "OtpFinishStep";
    private final ActivityResultRegistry registry;
    private ActivityResultLauncher<Intent> launcher;
    private final Context context;
    private final AtomicReference<OtpFinishStepCallback> otpFinishStepCallbackRef =
            new AtomicReference<>();

    public OtpFinishStep(Context context, @NonNull ActivityResultRegistry registry) {
        this.context = context;
        this.registry = registry;
    }

    @Override
    public void execute(@Nullable ProveAuthException otpException,
            OtpFinishStepCallback otpFinishStepCallback) {
        // We need to store callback object, it will be needed to complete this activity
        // by calling it with the results.
        otpFinishStepCallbackRef.set(otpFinishStepCallback);
        if (otpException instanceof OtpValidationException) {
            Log.e("OtpFinishStep", "found otp errors", e);
            return;
        }
        Intent intent = new Intent(context, OtpCodeInputActivity.class);
        launcher.launch(intent);
    }

    public void onCreate(@NonNull LifecycleOwner owner) {
        launcher = registry.register(OTP_FINISH_STEP_KEY, owner,
                new ActivityResultContracts.StartActivityForResult(),
                result -> {
                    OtpFinishStepCallback callback = otpFinishStepCallbackRef.get();
                    if (callback == null) {
                        return;
                    }

                    if (result.getResultCode() == Activity.RESULT_OK) {
                        Intent intent = result.getData();
                        if (intent != null) {
                            String code = intent.getStringExtra(
                                        IntentExtraFields.OTP_CODE_FIELD);
                            callback.onSuccess(new OtpFinishInput(code));
                            return;
                        }
                    }
                    callback.onError();
                });
    }
}