From a technical standpoint, PROFILE aims at investigating how to reconstruct the inner process of algorithms that exploit the information contained in user profiles. Our main objective is to make algorithms more accountable by increasing their transparency and opening them to the scrutiny of the public. In particular, we envision setting up a crowdsourcing platform in which users would directly contribute with their data without giving away their right to privacy. We also aim at providing effective tools to mitigate profiling. In this context, we focus on adapting the software diversification principles to protect against browser fingerprinting. Browser fingerprinting is a concrete and immediately relevant technology, which is currently not regulated at all. It has recently emerged as a powerful alternative to cookies for profiling and delivering targeted advertising. The study of browser fingerprinting is highly relevant for PROFILE because (1) it is extremely versatile and (2) currently there exists no effective protection against it. Its versatility comes from its simplicity: it consists in remotely collecting and storing information about a user’s browser. The complexity of modern browsers means that they directly provide unregulated access to hundreds of browser properties, ranging from the browser type to the status of the battery. While many existing browsers typically share individual properties, their combination acts a quasi-identifier and results in a statistically unique fingerprint that can be used for profiling. Unfortunately, the information contained in fingerprints is also needed for genuine and honest purposes, such as portability and usability (which originally motivated their introduction). Being able to disentangle genuine use from fingerprinting by analyzing the means of collection (usually in the form of obfuscated scripts in web pages) is therefore essential to characterize the risks for privacy. The versatile nature of fingerprinting also poses the major scientific challenge of devising effective mitigation techniques.