User Authorization at the Molecular Scale

Electronic user authorization systems help us maintain our privacy in many aspects of everyday life. However, the increasing difficulty to secure access and/or information digitally has inspired chemists to devise alternative, molecular approaches, in which users are identified by chemical means. The potential advantages of using molecular user authentication systems over conventional electronic devices are their versatility and unusual operating principles, which complicate replicating and, consequently, breaking into molecular security devices. Their molecular scale is another unique property that enables hiding such systems and, consequently, applying steganography as an additional layer of protection. Although the area of molecular‐based user authorization is still in its infancy, the development of various molecular keypad locks and, more recently, a password‐protected molecular cryptographic machine, indicate the possibility of protecting information at the molecular scale. Protected by Molecules: Over the last decade, a wide range of molecular keypad locks that can authorize unique chemical and optical “passwords” have emerged. This minireview outlines important developments in this field and highlights several potential advantages of using molecular security devices, which complicate bypassing them by unauthorized users. The possibility of combining molecular password protection with molecular cryptography and steganography is also discussed.