Remote On‐Paper Electrochemiluminescence‐Based High‐Safety and Multilevel Information Encryption

The escalating needs in information protection underscore the urgency of developing advanced encryption strategies. Herein we report a novel chemical approach that enables information encryption by on-paper electrochemiluminescence (ECL). Dendritic porous silica nanospheres modified with polyetherimide and bovine serum albumin were prepared as the chemical ink to write the secret message on a paper. Attaching the paper to an electrode, immersing it in a solution containing tris(2,2'-bipyridyl)ruthenium (Ru(bpy)₃ ²⁺) and then applying a suitable voltage, a remote "catalytic route" electrochemical reaction produces ECL that functions as the key to decrypt and visualize the message by imaging. In addition, proteins can be also used as the biological ink to write the secret message, which is then decrypted by a combined use of immunochemistry and ECL imaging as two keys. We believe the ECL-based strategy holds great promise in high-safety and multilevel information encryption, as it is protected not only by encoding, like conventional invisible inks, but also by the unique ECL decoding approach.