Unlocking Chemically Encrypted Information Using Three Types of External Stimuli.

Encryption is critical to information security; however, existing chemical-based information encryption strategies are still in their infancy. We report here a new approach to chemical encryption involving a supramolecular gel QR (quick response) code with multiple encryption functions. Three color "turn-on" supramolecular polymer gels, -, were prepared that produce pink, purple, and yellow colors when subject to treatment with acetic acid vapor, UV light, and methanolic FeCl, respectively. As the result of hydrogen-bonding interactions at the gel interfaces, the three gels can be assembled to produce gel . Engraving a QR code pattern onto then gave gel . When one or two stimuli are applied to the individual pieces corresponding to the QR engraved versions of the gels - making up , a complete scannable pattern is not displayed, and the stored information cannot be recognized. Only when three different stimuli are applied at the same time does give a complete recognizable pattern allowing the stored information to be retrieved. This strategy was applied to the decryption-based opening of a coded lock.