TypingDNA Recorder - Android

Table of contents

• About
• Overview
  • TypingDNARecorderMobile class
• Methods
  • TypingDNA.getTypingPattern (optionsObject)
  • TypingDNA.addTarget(element_id)
  • TypingDNA.removeTarget(element_id)
  • TypingDNA.reset()
  • TypingDNA.start()
  • TypingDNA.stop()
  • TypingDNA.pauseOverlay()
• Recommendations

About

The recorder captures user’s typing patterns.

It does so by recording timings based on keydown and keyup events, but also motion data related to the typing behavior (accelerometer, gyroscope, orientation).

Note: the Android version does not get the keydown events through the event notification system, therefore it needs a screen overlay to capture them. It is very important to include this in your apps. Also, please note that the recording might not work properly if the app allows swipe keyboards and autosuggestions or if emojis are used.

For the recorder to work, the TypingDNAOverlayService must be registered as a service in AndroidManifest.xml:

<application ...>
<service android:name=".typingdna.TypingDNAOverlayService" />
</application>

Also, please add the following permissions in AndroidManifest.xml:

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
<uses-permission android:name="android.permission.TYPE_APPLICATION_OVERLAY"/>

Overview

Use the TypingDNARecorderMobile class to capture user's typing patterns.

First you need to add the TypingDNARecorderMobile.aar library to your project. For instructions on how to do this please refer to our wiki.
You will need to record typing patterns when a user first creates his account and again whenever you want to authenticate that user on your platform.

TypingDNARecorderMobile class

Once you create an instance of the TypingDNARecorderMobile class, the user typing starts being recorded (as a history of key stroke events). Whenever you want to get the user's typing pattern you have to invoke .getTypingPattern method described in detail below.

private TypingDNARecorderMobile tdna;

protected void onCreate (Bundle savedInstanceState) {
   // ... code
  
  tdna = new TypingDNARecorderMobile(this);
  // start can be called later but not after the user starts typing
  tdna.start();
}

Note: The class should be instantiated on each View on which you want to record the typing pattern. When the app is not in foreground anymore, invoke the .pause() method (on the onPause() event) to pause the overlay and stop recording the sensors. Call the .stop() method as well on events such as onStop() or onDestroy(). Also, make sure to call .start() on the onResume() event. See recommendations and examples below.

Here are the methods of TypingDNARecorder class:

• getTypingPattern(params) ⇒ String
• addTarget(int targetId)
• addTargets(int[] targetIds)
• removeTarget(int targetId)
• removeTargets(int[] targetIds)
• start()
• stop()
• pause()
• reset()

Methods

a. TypingDNA.getTypingPattern (params)

This is the main function that outputs the user's typing pattern as a String

Definition:

public String getTypingPattern(int type, int length, String text, int textId, int target, boolean caseSensitive)

Other definitions, overriding the main one:

public String getTypingPattern(int type, int length, String text, int textId, int target)

public String getTypingPattern(int type, int length, String text, int textId)

Returns: A typing pattern in String form.

Parameters:

Param	Type	Description
type	int	0 for anytext pattern (when you compare random typed texts of usually 120-180 chars long).​ 1 for sametext pattern recommended in most cases, for emails, passwords, phone numbers, credit cards, short texts).​ 2 for extended pattern (most versatile, can replace both anytext and sametext patterns. Best accuracy, recommended in cases where text is not a secret)
textid	int	(Optional, only for type 1 and type 2) a personalized id for the typed text. (0 = ignore, the recorder will generate an id by hasing the entered text)
text	String	(Only for type 1 and type 2) a string that you want the typing pattern for
length	int	(Optional) the length of the text for which you want the typing pattern, for type 0 is usually 140 or more. 0 = ignore (works only if previous parameter 'text' = “”)
target	String	Specifies from which target the pattern should be obtained from.
caseSensitive	Boolean	(Optional, default: false) Used if you pass a text for type 1

Example:

int type = 1;
int length = 0; //optional
String textToType = "Please type this sentence to get authenticated.";
int textId = 0; //optional
boolean caseSensitive = false; //optional
String targetId = nameInput.getId();

String typingPattern = tdna.getTypingPattern(type, length, textToType, textId, targetId, caseSensitive);

b. TypingDNA.addTarget(int targetId)

Adds a target to the recorder. You can add multiple elements. All the typing events will be recorded for this component.

Definition:

public void addTarget(int targetId)

Other definition, overriding the main one:

public void addTarget(int[] targetIds)

Example:

private TypingDNARecorderMobile tdna;

protected void onCreate (Bundle savedInstanceState) {
    // initialize tdna here
    
    tdna.addTarget(usernameInput.getId());
    tdna.addTarget(passwordInput.getId());
    tdna.addTarget(textInput.getId());
}

c. TypingDNARecorderMobile.removeTarget(int targetId)

Remove a target from the targetIds array.

d. TypingDNARecorderMobile.reset()

Resets the history stack of recorded typing events.

e. TypingDNARecorderMobile.start()

It starts the recording of typing events. This method should be called at initialization or after a .stop() or a .pause(), to resume recording. Example:

@Override
protected void onResume(){
   //Starts recording the typing evens and also starts the overlay service.
   tdna.start();
   super.onResume();
}

f. TypingDNARecorderMobile.stop()

Ends the recording of further typing events. It can be invoked on such events as onDestroy() or onStop(). Example:

@Override
protected void onDestroy() {
   //Stops the overlay service and ends the recording of further typing events.
   tdna.stop();
   super.onDestroy();
}

@Override
protected void onStop(){
   //Stops the overlay service and ends the recording of further typing events.
   tdna.stop();
   super.onStop();
}

g. TypingDNARecorderMobile.pause()

Pauses the overlay and the sensors. We recommend you call this method on the onPause event, like in the following example:

@Override
protected void onPause(){
   //Stops the overlay service and ends the recording of further typing events.
   tdna.pauseOverlay();
   super.onPause();
}

Recommendations

We recommend that you deactivate autocorrect & predictive features for the text field(s) you want to record on. You can achieve this by setting inputType to textVisiblePassword.

For mobile apps, we recommend you use type 1 or type 2 typing patterns. The type 1/2 patterns work well with 15-30 chars of text, while type 0 pattern needs much more data to have good accuracy (120-150 chars of text).

For types 1/2 we recommend at least 3 enrolled patterns for a good accuracy.