Precisely regulation of photochromism via absorption-induced photoreaction attenuation and light intensity dependence for time-resolved asymmetric encryption

Abstract

With the growing need for secure information storage, encryption materials are required to be designed with high information capacity, easy to prepare, and hard to decode. Here, donor–acceptor Stenhouse adducts (DASAs), known for their straightforward synthesis, are used to develop a new time-resolved asymmetric encryption strategy, enhancing information capacity. The photoswitching property of DASAs is regulated by the intensity of initial absorbance and the intensity of light irritation. Besides, we recognize the relationship between the intensity of initial absorbance and photoswitching rate constant is caused by the absorption-induced photoreaction attenuation (AIPA). By rationally regulating the photo-bleching time of DASAs, the information can be sequentially revealed (colored state) or concealed (bleached state) in the desired temporal order. As a result, a quick response (QR) code label for practical application and a multi-level encoding scheme for sophisticated asymmetric encryption have been proposed. Specifically, the advanced asymmetric encryption technique employs layer sequence and light intensity as private keys, diverging from traditional public key systems. Information is sequentially displayed over time. The accurate information can only be revealed at the correct temporal dimension (layer sequence) and the appropriate decoding parameter (light intensity), both of which are precisely controlled by AIPA. This study not only unveils an approach to time-resolved asymmetric encryption using DASAs, enhancing the security and capacity of information storage, but also paves the way for the development of high-security encryption materials that are both highly efficient and resistant to unauthorized decoding efforts.