RapporJS

This is a provisional implementation of Google's RAPPOR algorithm in JavaScript that is designed to handle categorical data. It should be used in conjuction with RapporJS

Setup

Embed the following line of code into a website your respondents will visit

<script src="http://cdn.rapporjs.com/rappor.min.js">

Quick Start

After navigating to the Users page, you'll generate client-side code like this:

r = new Rappor( {publicKey: "generated_from_/users"} );

r.send(some_string, {freq: "instant"});

which you can use to send data. These two operations - creating a Rappor object and calling send() on it - are the two main ways to call (and customize) the client-side code. Different options are given in the API section below

API

Creating a Rappor object

Generally, all options below are in the format:

r = new Rappor( {option1: value1, option2: value2, ...} );

Below, for each option I supply the name and the value to change it

Parameters

By default, Rappor uses these parameters (for reasons given in thesis.pdf):

default_params = {k: 32, h:2, p:0.1, q:0.8, f:0.81, m:128, server:"http://rappor-js.herokuapp.com/api/v1/records"};

To change specific parameters, supply them in the same format. For example, to change m to 64 and server to "http://url_of_your_choice.com" (and keep everything else as in default_params), add the params option below to the instantion of a Rappor object:

params = {m: 64, server="http://url_of_your_choice.com"}
r = new Rappor( {params: params} );

publicKey

If you're using your own server, then you can also specify your own publicKey (default is the empty string):

params = {m: 64, server="http://url_of_your_choice.com"};
pK = "my_special_key";
r = new Rappor( {params: params, publicKey: pK} );

Calling send()

send() provides further option choices, and will result in a JSON object being sent via a POST request to the server specified in the Rappor() instantiation:

example = {
	cohort: <cohort>,
	irr: "010010101" etc,
	params: {k: 32, h:2, p:0.1, q:0.8, f:0.81, m:128, server:"http://rappor-js.herokuapp.com/api/v1/records"},
	group: <publicKey>
}

Frequency

To send a report whenever a client lands on a page, set freq to "instant". To send a report at most hourly, set freq to "hourly", and so on for "daily", "weekly", and "monthly". For example, to send the string "dog" daily,

r = new Rappor();
r.send("dog", {freq: "daily"} )

Number of Reports

To send a report multiple times, you can set a parameter n appropriately (don't call send() lots of times because it is asynchronous). For example, to send "dog" 10 times,

r = new Rappor();
r.send("dog", {n: 10} )

Note: this should only be used for testing purposes - sending the same report multiple times from the same client can degrade the privacy guarantees

Callback

You can specify an optional callback function when send() has finished. For example, to alert the user after "dog" has been sent 10 times:

var callback = function() { alert("done!"); };

r = new Rappor();
r.send("dog", {n:10, callback: callback} );

Other Stuff

In some cases, it can be useful to be able to call send() without any arguments (e.g. when it's a callback to a different function). For these situations, you can use:

r = new Rappor();
r.sendTrue();
r.sendFalse();

Which will send "true" and "false" respectively with the same options as send() has.