Why Software Fails at Trust Boundaries

What happens when perfectly valid data crosses into the wrong place? This episode explores Habit 1 of the 13 habits from Effective Secure Coding: Think in Trust Boundaries. Why do secure values become dangerous when they move between users, services, files, APIs, databases, or privilege levels? And what changes when AI is writing the code for you? We look at how to spot trust boundaries, make them explicit in your design, and give AI coding tools concrete security constraints instead of vague instructions like “make it secure.” Secure coding starts with one question: where does trust change?