Expert in information security and reverse engineering, Esther Onfroy aka U039b is a French hacktivist, lecturer and co-founder and main maintainer at PTS. She is also co-founder of Defensive Lab Agency, Exodus Privacy (French non-profit organization that fights against tracking SDKs in Android apps), Pithus (open source mobile threat intelligence platform), Echap (French non-profit organization that fights against the use of technology in violence against women), La Résille (French non-profit organization of hackers producing feminist science-fiction). She fights against surveillance capitalism and has contributed to several investigations highlighting the illegal data collection carried out by major digital actors. She helps journalists, academics and NGOs to better understand the issues of cybersecurity and surveillance on mobile devices.

Esther works closely with the LGBTQ+ community on creating tools and protocols that fight against gender based violence facilitated by information and communication technologies. With Echap, she works with women’s shelters. She has been working with NGOs and HRDs for 8 years.