# Two‐Factor Authentication Inspired Optical Security of Information Enabled by Silica Nanofibers

## TL;DR

This paper introduces a material-based security system inspired by two-factor authentication, using silica and fluorescent nanofibers to control access to hidden information.

## Contribution

The study presents a novel material-based encryption system that mimics two-factor authentication using liquid- and light-responsive nanofibers.

## Key findings

- A composite film of silica and fluorescent nanofibers can switch from opaque to transparent when wetted.
- Fluorescent patterns become visible only after UVA light exposure following liquid activation.
- The system requires sequential use of liquid and UVA light as decryption keys, mimicking digital two-factor authentication.

## Abstract

Two‐factor authentication (2FA) is widely used in informatics for identity verification and information encryption, yet its applications in materials science remain largely underexplored. In this study, a composite film composed of silica nanofibers (NFs) and fluorescent nanofibers (FNFs) is presented, offering a unique material‐based approach to 2FA encryption. NFs and FNFs are synthesized via water‐in‐oil emulsions, resulting in films that can be both liquid‐ and light‐responsive. NFs assembly exhibits intriguing light‐scattering characteristics, rendering it opaque under normal conditions but transparent when wetted, functioning as a liquid‐triggered optically shielding material. Embedded FNFs remain concealed within NF matrix, becoming fluorescently visible only under ultraviolet A (UVA) light illumination of specific wavelength. The encryption system requires two decryption keys − liquid and UVA light, which must be applied sequentially to successfully access the encoded information. Upon liquid exposure, the film transitions from opaque to transparent, allowing light transmission. Subsequent UVA irradiation reveals the hidden fluorescent patterns labeled by FNFs in film. This sequential encryption−decryption mechanism mimics the principles of 2FA in digital data systems, providing a promising new paradigm for secure information storage and transmission for patterns using material‐based strategies.

Inspired by the principles of two‐factor authentication in data informatics, a material‐based optical security encryption−decryption system is developed using silica nanofibers and fluorescent nanofibers. The engineered film exhibits unique liquid‐ and light‐responsiveness, enabling two‐level sequential encryption and decryption, which provides a promising new paradigm for secure information storage and transmission.