This post is also available in:
עברית (Hebrew)
A new material developed by researchers offers a promising route to secure, tamper-proof authentication for physical objects. At the heart of the innovation is a conductive hydrogel that produces a unique and physically unclonable signal every time it is activated, potentially transforming how industries safeguard high-risk components like microchips, implants, and electronics.
The system works by embedding a soft hydrogel with a microscopic internal structure that cannot be replicated, even with full knowledge of how it was made. The material, created using a technique called regional assembly crosslinking (RAC), blends two components: polypyrrole (PPy), which conducts electricity, and polystyrene sulfonate (PSS), which supports ion movement.
According to Interesting Engineering, when formed under an electric field, the hydrogel organizes into a three-dimensional network of ion-electron junctions. Each junction responds slightly differently to electrical input, and the overall response is shaped by the material’s internal randomness—effectively becoming a physical fingerprint that can’t be cloned.
When electrical pulses are sent through the material, the output signal reflects the unique internal structure. Even after running the same input thousands of times, the system gives nearly identical results, confirming its high reliability. Researchers estimate that the device can generate more than 10¹⁹ distinct challenge-response pairs, far exceeding cryptographic security standards (1010).
The hydrogel’s performance also holds up under scrutiny. Voltage response times are quick—rising to 90% of peak in just 13 milliseconds and dropping to 10% within 49 milliseconds—indicating efficient charge movement across the gel. Even machine learning algorithms trained on large datasets failed to accurately predict the outputs, suggesting strong resistance to spoofing.
In practice, this could enable manufacturers to embed unforgeable signatures into devices, components, or packaging—offering a low-cost, scalable alternative to traditional physical authentication methods like barcodes or holograms.
While the technology is still under development, the approach combines low fabrication costs with a high level of security. While further work is required, including real-world testing across industries, to improve durability and integrate the material into a wider range of products, it shows promise of bringing the concept of built-in, tamper-proof identity closer to market.
The research was published in the Advanced Materials Journal.
