Authentication systems typically fall into two categories: deterministic systems that resolve identity with certainty and probabilistic systems that rely on interpretation or behavioral signals. Understanding the difference between these models is critical when evaluating technologies used for product authentication, infrastructure verification, and security-sensitive environments.

Organizations use a wide range of technologies to protect products from counterfeiting, diversion, and fraud. From QR codes and RFID chips to holograms and covert forensic markers, each approach offers different trade-offs in security, cost, and operational complexity. This guide compares the most widely used anti-counterfeiting technologies and explains how authentication systems detect duplication and verify identity.

QR codes are widely used for logistics, marketing, and product engagement, but they were never designed to prevent cloning. Because QR codes contain readable identifiers, duplicating the image typically preserves the same function. This article explains how QR code cloning works, why serialization alone does not solve the problem, and what authentication systems must do differently to detect duplication.