Peter Eckersley, a co-founder of Let's Encrypt and a prominent figure in the field of computer security, has passed away at the age of 44. He was a key player in the development of several important projects, including Let's Encrypt, Certbot, and HTTPS Everywhere. Eckersley's work focused on improving internet security and privacy, and he was also involved in research on artificial intelligence and its ethics. He will be remembered for his significant contributions to the field of computer science and his commitment to making the internet a safer and more secure place.