A photographic portrait of Dillon Dieffenbach
Critical infrastructure companies can no longer afford to accept less – we must treat cybersecurity as a fundamental component of system reliability.

Dillon G. Dieffenbach

EY Japan Cybersecurity Leader

People-first leader with a global mindset. Practical experience in protecting critical infrastructure. Strategic thinker. Problem solver. Team builder. Traveler, golfer, proud father and husband.

Dillon leads EY Japan's cybersecurity team, which helps Japanese companies, as well as organizations doing business in Japan, to improve their cyber risk profile. EY Japan provides a full range of cybersecurity assessment and advisory services, which are tailored to specific industry needs.

For example, recent projects have included full-service implementation of a large-scale Identity and Access Management (IAM) technology solution, targeted red-teaming and cyber vulnerability management assessments, and transformation of multiple clients’ cybersecurity program governance.

Prior to joining EY, Dillon was responsible for leading IT risk management and compliance at a national US financial services company, where he reported directly to the CEO. There, he also assisted in defining and leading the execution of IT initiatives in support of the business strategy.

He earned a BA in Accounting and a BBA from Furman University.

How Dillon is building a better working world

“In my current role, I have the amazing opportunity to work with truly diverse teams to help the world’s leading companies better manage their cyber risks. In the Transformative Age, working with talented professionals to build and protect digital trust is my way of helping to build a better working world.”

Contact Dillon