Security-Enhanced 3D Data Encryption Using a Degradable pH-Responsive Hydrogel

Abstract

Based on degradable pH-responsive hydrogel, we report on an enhanced three-dimensional data encryption security technique in which a pH value is used for information manipulation. Featuring three types of states upon the pH value variation, namely, shrinkage, expansion and degradation, the hydrogel renders a limited pH value window as the “key” for information decryption. The pH-dependent shrinkage-to-expansion conversion of the hydrogel leads to a threshold pH value for retrieving the recorded data, whilst the degradability of the hydrogel, which can be tuned by adjusting the composition ratio of PEGDA/AAc, gives rise to a second threshold pH value for irreversibly sabotaging the retrieved data. Pre-doping silver ions in the hydrogel facilitates explicit recording and reading of binary data in forms of three-dimensional silver patterns through photoreduction and scattering, respectively, with a femtosecond laser. By accurately matching the vertical spacing of the encoded silver nanopatterns with the diffraction-limited focal depth of the decryption microscope, we can tune the pH value to encrypt and retrieve information recorded in layers and set a critical pH value to smash encoded information, which proves a highly secured 3D data encoding protocol. This strategy can effectively enrich data encryption techniques, vastly enhancing data security within unattained chemical dimensions.

Phase‐Transition‐Triggered Optical Switching for Multistage Information Encryption/Decryption

“…Our previous work demonstrated that hydrogel with high water‐swelling ratio in length >5 could provide an effective platform for laser‐printing information encryption. [ 44 ] Therefore, the high swelling ability of OS gel in water was another essential factor for the information encryption/decryption, which was obtained by the charge‐to‐charge repulsion of MPTAC groups in the hydrophilic PAM network. Upon being immersed in water, the charge‐to‐charge repulsion enabled the expansion of the hydrophilic PAM network, which allowed more water molecules to be absorbed into OS gel.…”

“…This diffuse reflection‐induced decrypting mechanism was similar to that in our previous report. [ 44 ] Based on the HSV model, the brightness of laser‐cutting area was 30% under daylight and increased to 60% under strong white light, which meant that the information was not visible in daylight but visible in strong white light, leading to a cycle of encryption and decryption (Figure S18, Supporting Information). Therefore, OS gel could be used to create an optical‐switching gel system for multistage information encryption/decryption triggered by water swelling‐induced phase transition, which is expected to provide a new type of information‐storage platform with improved security.…”

“…[43] However, there are few reports on a gel system that is capable of water swelling-induced opticalswitching for multistage information encryption/decryption. [44,45] Probably, this gel system is still limited by elaborate structural design and complex stimulus conditions. [46] Our previous work reported a swelling-induced switching of light reflection/penetration for information camouflage and encryption on a hydrogel surface, [47] which inspired us to further explore the innovative research on water swelling-induced optical switching for multistage information encryption/decryption.…”

Biomembrane-Based Nanostructure- and Microstructure-Loaded Hydrogels for Promoting Chronic Wound Healing

“… 74 Nanostructures and microstructures can be released from hydrogels when exposed to certain stimuli, such as temperature, pH, enzymes and magnetic fields. 75 , 76 …”