Zhongda Team Proposes New Dual Information Encryption Strategy - Sun Yat-sen University News Website

Advanced Encryption Strategy Using Supramolecular Interactions and Shape Memory Hydrogels - Abstract In a significant advancement in the field of information security, a research team from Sun Yat-sen University, led by Professor Jun Fu, has developed a novel dual information encryption strategy. This innovative approach integrates supramolecular interactions with the shape memory properties of hydrogels, offering a robust, flexible, and reprogrammable method for encrypting and decrypting information. The strategy leverages the unique properties of a synthesized fluorescent molecule, Naphthalimide-bridged β-Cyclodextrin (N-CD), and a polymer brush (PBG) grafted with Adamantane (Ada) molecules on the surface of a shape memory hydrogel. **Key Events and Findings:** 1. **Synthesis of N-CD and PBG:** The team synthesized N-CD, a fluorescent molecule, and grafted PBG, a polymer brush containing Ada molecules, onto the surface of a shape memory hydrogel. The interaction between N-CD and Ada molecules enables the anchoring of N-CD to the hydrogel surface, facilitating the writing of fluorescent information. 2. **Reversible Fluorescence Mechanism:** The fluorescence of N-CD is regulated through a reversible mechanism involving π-π stacking and intramolecular charge transfer (ICT). When N-CD is bound to Ada, the fluorescence is quenched due to the formation of a π-electron donor-acceptor pair. This quenching can be reversed by removing the quencher, allowing for the erasure, recovery, and reprogramming of information. 3. **Information Writing and Encryption:** Information can be easily written onto the PBG surface using N-CD as "ink." This includes patterns, letters, and even QR codes, which can be read by smartphones under UV light. The combination of fluorescence and shape memory properties of the hydrogel provides a dual layer of encryption. 4. **Shape Memory Hydrogel for Physical Encryption:** The hydrogel can be folded into temporary three-dimensional shapes, such as a rose, which hide the fluorescent information. Upon hydration, the hydrogel returns to its original flat shape, revealing the encrypted information under UV light. This physical transformation adds an additional layer of security. 5. **Selective and Specific Information Erasure:** The team discovered that trinitrophenol (PA) can specifically quench the fluorescence of N-CD by forming a π-electron donor-acceptor pair with the naphthalimide moiety. This allows for the selective erasure of information, which can then be reprogrammed with new data. The process can be reversed using a Na2CO3 solution, which reacts with PA to restore the fluorescence. 6. **Application to Complex Surfaces:** The encryption strategy can be applied to irregular surfaces, enhancing its practicality. By using the unique structures of animals and insects, such as the spines of a starfish or the wings of a butterfly, the team created advanced, biologically inspired encryption systems. These systems not only hide information but also increase the complexity and difficulty of decryption. **Implications and Significance:** The dual information encryption strategy developed by Professor Fu's team offers several advantages over existing methods. It is highly selective and specific, reducing the risk of non-specific decryption or information loss. The reversibility of the encryption process allows for repeated writing, erasing, and reprogramming of information, making it suitable for dynamic and secure communication systems. Furthermore, the combination of supramolecular interactions and shape memory properties provides a multi-modal approach to encryption, enhancing the overall security and flexibility of the system. This research, titled "Erasable, Rewritable, and Reprogrammable Dual Information Encryption Based on Photoluminescent Supramolecular Host-Guest Recognition and Hydrogel Shape Memory," was published in the prestigious journal *Advanced Materials*. The study highlights the potential of this new method in various applications, including secure communication, data protection, and advanced information systems. It also opens up new avenues for the development of novel encryption materials, contributing significantly to the field of information security. **Collaboration and Funding:** The research was a collaborative effort between Sun Yat-sen University and Ningbo Institute of Technology. It was supported by the National Natural Science Foundation of China and the Ministry of Industry and Information Technology. The first author of the paper is Hai-Long Yang, a doctoral student from the School of Materials Science and Engineering at Sun Yat-sen University, with Professor Jun Fu and Associate Professor Yang Cong from Ningbo Institute of Technology as co-corresponding authors. **Conclusion:** The novel dual information encryption strategy developed by Professor Jun Fu's team at Sun Yat-sen University represents a significant breakthrough in the field of information security. By integrating supramolecular chemistry with the shape memory properties of hydrogels, the team has created a versatile and secure method for encrypting and decrypting information. This approach not only enhances the complexity and difficulty of decryption but also offers the potential for repeated use and reprogramming, making it a promising technology for future secure communication systems.