Josh Aas co-founded and currently runs Internet Security Research Group (ISRG), the nonprofit entity behind Let's Encrypt, the world's largest certificate authority helping to secure more than 290 million websites. He also spearheaded ISRG’s latest projects, one focused on bringing memory-safe code to security-sensitive software, called Prossimo, and Divvi Up, a privacy-respecting metrics service. Josh worked in Mozilla’s platform engineering group for many years, improving the Firefox web browser. He also worked for Mozilla in a senior strategy role, helping to find solutions for some of the Web's most difficult problems. He has deep expertise in software security and ecosystem dynamics, as well as organizational leadership.