A few years ago, a customer handed us a report from a Big 4 consulting firm describing how, after close to 100 person-hours of review, a team of ‘highly-qualified senior security engineers’ had failed to find any flaw in their encrypted communications product. Half a day later, I had worked out how to break the product’s encryption, and demonstrated a working exploit. The customer was confused—why hadn’t the well-dressed consultants caught the vulnerability?