Phys.org June 11, 2024 An international team of researchers (USA – Harvard University, MIT, University of Chicago, Germany) introduced “pseudomagic” ensembles of quantum states that are computationally indistinguishable from those with high nonstabilizerness. They demonstrated that pseudomagic neither follows from pseudoentanglement nor implies it. It offers fresh insights into the theory of quantum scrambling: it uncovers states that, even though they originated from nonscrambling unitaries, remain indistinguishable from scrambled states to any physical observer. Applications include new lower bounds on state synthesis problems, property testing protocols, and implications for quantum cryptography. According to the researchers only quantities measurable by a […]
Category Archives: Cryptography
New technology developed for quantum cryptography applications
Phys.org May 10, 2023 Temporal modes (TMs), an encoding basis based on the time-frequency degree of freedom of photons, represent one of the most promising high-dimensional alphabets. TM-based quantum communication has until now been limited to a two-dimensional space due to the lack of a suitable decoder. However, quantum communication protocols based on single-photon TMs require suitable multichannel decoders. Researchers in Germany have demonstrated a new device that facilitates demultiplexing of high-dimensional TMs of single photons, and implemented a complete five-dimensional decoder that enables TM-based high-dimensional quantum key distribution. They showed that it is possible to scale the presented decoder […]
Researchers develop phase-change key for new hardware security
Nanowerk November 18, 2022 An international team of researchers (Singapore, UK, South Korea) has developed a new type of hardware security device called physical unclonable function (PUF) using phase-change materials. They fabricated devices switch reversibly between the glassy amorphous state and crystal orderly state. Then they used the variation in the device’s electrical conductance to construct the PUF due to the inherent randomness arising from the manufacturing process, which is not shown by conventional silicon-based devices. They modelled the characteristics of actual phase-change devices to generate a simulation of many phase-change-based PUFs and tested their security using machine learning. They […]
An uncrackable combination of invisible ink and artificial intelligence
Phys.org May 5, 2021 Even as electronic records advance, paper is still a common way to preserve data. Researchers in China have developed a paper information protection scheme by combining fluorescent invisible ink and artificial intelligence. The ink was prepared by dissolving carbon nanoparticles in water, which has a high quantum yield and outstanding light stability and salt stability, thus ensures the integrity of information in complex environments. A neural network was specially trained based on ultraviolet light excited symbols printed by invisible ink. Using this scheme, the correct information could only be read with the specially trained neural network […]
A display that completely blocks off counterfeits
EurekAlert January 22, 2021 Researchers in South Korea have developed a device using nanostructures that is capable of encrypting full-color images depending on the polarization of light. The on and off states can be adjusted according to the polarization of the incident light. It displays full-color images during the on state and shows no images in the off state and it can switch between different images. According to the researchers this feature can be utilized as an anti-forgery device security label that appears to be a simple color image to the naked eye but reveals the serial number when a […]