Programmable Encryption Based on Photochromism of Spiropyrans and Donor–Acceptor Stenhouse Adducts

Abstract Improving information security is a persistent challenge for conventional secrecy approaches such as single and double encryption. In this work, programmable encryption is reported, involving multiple stimuli to independently control different encrypted information, to boost data security. The linear‐cyclic isomerization of donor–acceptor Stenhouse adducts (DASAs) and spirocyclic‐merocyanine (SC‐MC) isomerization of spiropyrans (SPs) on paper substrate surface are optimized by integration of ester‐contained functional molecules, making them be controlled by light irradiation and heat. By controlling the sequence of three inputs (UV light, visible light, heat), the hybrid encrypted message combining DASAs and SPs exhibits distinct outputs. The encrypted message can be recorded in various forms including characters, text, and figures. Because of the multiplied number of outputs, this method offers a straightforward and powerful solution for safeguarding data in different contexts, which enhances clarity and effectiveness, ensuring resistance to tampering and counterfeiting of the encrypted information.