Assaf serves as Chief Information Security Officer & VP, Enterprise Cyber Security at PayPal, where he oversees all aspects of PayPal’s global security product and service delivery organization. Assaf provides strategic leadership for PayPal Security’s First Line of Defense team, which builds security products, manages security infrastructure, and provides security services for the company’s customer base.

Assaf started his career in Information and Cyber Security in the Israeli defense forces in 2000. After his military service, he joined the Israeli Ministry of Finance as the Chief Information Security Officer of the government ISP and eGovernment unit.

In 2010, Assaf co-founded CyberVision, a company which detected malicious software's command and control channels using AI/ML technologies, which was acquired by Verint Systems in 2011. Assaf then led product management for Verint's Cyber Defense business focusing on developing country-level cyber defense capabilities. In 2013, he co-founded SenseCy, a cyber intelligence company focusing on the acquisition and analysis of malware traded on the darknet and in underground forums.

In 2020, Assaf joined the Google CISO Customer Advisory Board, and 2021, Assaf joined the board of advisors for Arnica, a DevSecOps startup, and SafeBreach, a PayPal portfolio company focusing on Breach and Attack Simulation. Assaf currently serves on the board of directors of the Arizona Technology Council.

Since 2018, Assaf has been a mentor in the Israeli-American Council's Eitanim project, an entrepreneurship program aimed at helping middle and high school youth learn how to envision, create and execute a business plan.