Disordered photonic structures are promising materials for the realization of physical unclonable functions (PUF), physical objects that can overcome the limitations of conventional digital security methods and that enable cryptographic protocols immune against attacks by future quantum computers. One PUF limitation, so far, has been that their physical configuration is either fixed or can only be permanently modified, and hence allowing only one token per device. We show that it is possible to overcome this limitation by creating a reconfigurable structure made by light-transformable polymers, in which the physical structure of the unclonable function itself can be reversibly reconfigured. We term this novel concept Hyper PUF or HPUF in that it allows a large number of physical unclonable functions to co-exist simultaneously within one and the same device. The physical transformation of the structure is done all-optically in a reversible and spatially controlled fashion. Our novel technology provides a massive enhancement in security generating more complex keys containing a larger amount of information. At the same time, it allows for new applications, for example serving multiple clients on a single encryption device and the practical implementation of quantum secure authentication of data.

翻译：无序光子结构是物理不可克隆函数（PUF）的理想材料，这种物理对象能够突破传统数字安全方法的局限，并实现可抵御未来量子计算机攻击的加密协议。然而，目前PUF的局限在于其物理构型要么固定不变，要么只能被永久性修改，因此每个设备仅能拥有一个标识。我们证明，通过构建由光转换聚合物制成的可重构结构，其中不可克隆函数的物理结构本身可实现可逆重构，从而能够突破这一限制。我们将这一创新概念命名为"超PUF"（Hyper PUF或HPUF），因为它允许同一设备内同时共存大量物理不可克隆函数。该结构的物理转换以全光学方式实现，具有可逆性和空间可控性。我们的新技术通过生成包含更丰富信息的更复杂密钥，极大提升了安全性。同时，它还能支持诸多新应用，例如在单一加密设备上服务多个客户端，以及实现数据的量子安全认证实用方案。