Chiral Cryptographic Key‐Based Fluorescence Encryption Enabled by Stimuli‐Responsive Metal‐Organic Frameworks

The increasing threats of data forgery and security breaches necessitate the development of advanced encryption strategies beyond traditional cryptographic methods. Fluorescence‐based encryption has emerged as a promising alternative, yet current systems suffer from low security due to simple, reversible stimuli responses. Here, we introduce a novel lock‐and‐key encryption system using a chiral cyclodextrin‐based metal‐organic framework (CDMOF), termed Zole@CDMOF (Zole = acetylated benzoimidazole), for enantioselective discrimination of phenylethylamine (PEA) enantiomers. In this framework, the confined Zole guest serves as the lock, while PEA enantiomers act as the key, selectively triggering fluorescence turn‐on via acetyl‐O bond cleavage and restoring excited‐state intramolecular proton transfer (ESIPT) of deacetylated Zole. Mechanistic studies reveal that enantioselectivity arises from thermodynamic differences and distinct hydrogen‐bonding interactions between PEA enantiomers. To enhance practical application, Zole@CDMOF is fabricated into a flexible sensor via a simple scotch tape strategy, enabling direct visual indexing of enantiomeric excess. Additionally, we propose a barcode‐based chiral encryption model, establishing a quadruply encrypted system with ultra‐high security—allowing only one out of approximately two million keys to unlock the data. This study pioneers the first chiral cryptographic key in fluorescence encryption, paving the way for ultra‐secure encryption, advanced chiral sensing, and stimuli‐responsive materials.