Trusted by Design, Exposed by Convergence is a forensic, unflinching exploration of how the implicit trust that once governed industrial systems has become their greatest vulnerability. In this sweeping and incisive work, cybersecurity expert Bill Johns exposes the hidden risks embedded in legacy operational technology (OT) environments-systems that were never meant to face adversaries, and yet now operate in a world where cyber threats have not only arrived, but evolved to exploit the very assumptions these systems were built on.
This book traces the full arc of that evolution-from the analog roots of industrial control to the networked chaos of the present-laying bare how protocols like Modbus, DNP3, OPC Classic, and BACnet were designed in an era without enemies, and how those same protocols are now fielding attacks in environments they were never equipped to defend. Through real-world incidents, technical analysis, and field stories from power plants, refineries, and smart buildings, Johns reveals a sobering truth: security isn't just about malware, firewalls, or patching-it's about architecture, trust models, and a history of design choices that still shape our most critical systems today.
More than a catalog of vulnerabilities, Trusted by Design is a narrative of convergence-where the priorities of IT and OT collide, where the battle between availability and integrity plays out not in code but in the control rooms of factories and substations. It dives deep into insider threats, the culture clash between engineers and cybersecurity professionals, and the challenges of adapting industrial systems to a threat landscape that was once foreign but is now inescapable. It explores vendor defaults left exposed, firmware backdoors never meant to see the light of day, and the deceptive convenience of remote access features that silently bridged once-isolated networks to the open internet.
Yet despite the gravity of the risks, this book is not alarmist-it is strategic. It doesn't just chart the problems, it maps the response. Layered defenses, micro-segmentation, protocol-aware inspection, deception technologies, and cyber-physical monitoring are dissected not as buzzwords, but as viable, field-tested solutions. Johns gives voice to the security analysts, engineers, and operators grappling with impossible trade-offs and shows how thoughtful architecture, cooperative defense, and cultural alignment between IT and OT can restore resilience without sacrificing reliability.
What sets Trusted by Design apart is its humanity. This is a book written with empathy-for the technician trying to maintain an unpatchable PLC, the operator navigating a live-fire red team exercise, the incident responder tracing an attack vector through an invisible trust path, and the policymaker struggling to regulate systems built without a single line of secure code. It's a work grounded in reality and field experience, but framed with clarity and precision-offering not just explanations, but insight.
For cybersecurity professionals, industrial engineers, risk managers, policymakers, and infrastructure defenders, Trusted by Design, Exposed by Convergence is essential reading. It is a rare blend of history, engineering, and strategic foresight. It challenges long-held assumptions and reveals why securing critical infrastructure begins not with firewalls or threat feeds, but with questioning the very foundations of trust.
Because the network has enemies now. And too many of our systems still trust them.
