Conventional quantum key distribution (QKD) typically uses binary encoding based on photon polarization or time-bin degrees of freedom and achieves a key capacity of at most one bit per photon. Under photon-starved conditions the rate of detection events is much lower than the photon generation rate, because of losses in long distance propagation and the relatively long recovery times of available singlephoton detectors. Multi-bit encoding in the photon arrival times can be beneficial in such photonstarved situations. Recent security proofs indicate high-dimensional encoding in the photon arrival times is robust and can be implemented to yield high secure throughput. In this work we demonstrate entanglement-based QKD with high-dimensional encoding whose security against collective Gaussian attacks is provided by a high-visibility Franson interferometer. We achieve unprecedented key capacity and throughput for an entanglement-based QKD system because of four principal factors: Franson interferometry that does not degrade with loss; error correction coding that can tolerate high error rates; optimized time-energy entanglement generation; and highly efficient WSi superconducting nanowire single-photon detectors. The secure key capacity yields as much as 8.7 bits per coincidence. When optimized for throughput we observe a secure key rate of 2.7 Mbit s −1 after 20 km fiber transmission with a key capacity of 6.9 bits per photon coincidence. Our results demonstrate a viable approach to high-rate QKD using practical photonic entanglement and single-photon detection technologies.

Abstract-Homomorphic encryption, aimed at enabling computation in the encrypted domain, is becoming important to a wide and growing range of applications, from cloud computing to distributed sensing. In recent years, a number of approaches to fully (or nearly fully) homomorphic encryption have been proposed, but to date the space and time complexity of the associated schemes has precluded their use in practice. In this work, we demonstrate that more practical homomorphic encryption schemes are possible when we require that not all encrypted computations be supported, but rather only those of interest to the target application. More specifically, we develop a homomorphic encryption scheme operating directly on integer vectors that supports three operations of fundamental interest in signal processing applications: addition, linear transformation, and weighted inner products. Moreover, when used in combination, these primatives allow us to efficiently and securely compute arbitrary polynomials. Some practically relevant examples of the computations supported by this framework are described, including feature extraction, recognition, classification, and data aggregation.

Quantum key distribution (QKD) enables participants to exchange secret information over long distances with unconditional security. However, the performance of today's QKD systems is subject to hardware limitations, such as those of available nonclassical-light sources and single-photon detectors. By encoding photons in high-dimensional states, the rate of generating secure information under these technical constraints can be maximized. Here, we demonstrate a complete time-energy entanglement-based QKD system with proven security against the broad class of arbitrary collective attacks. The security of the system is based on nonlocal dispersion cancellation between two time-energy entangled photons. This resource-efficient QKD system is implemented at telecommunications wavelength, is suitable for optical fiber and free-space links, and is compatible with wavelength-division multiplexing.

It is highly desirable to design a single modality that can simultaneously trigger apoptosis and ferroptosis to efficiently eliminate tumor progression. Herein, a nanosystem based on the intrinsic properties of tumor microenvironment (TME) is designed to achieve tumor control through the simultaneous induction of ferroptosis and apoptosis. CuCP molecules are encapsulated in a liposome‐based nanosystem to assemble into biocompatible and stable CuCP nanoparticles (CuCP Lipo NPs). This nanosystem intrinsically possesses nanozymatic activity and photothermal characteristics due to the property of Cu atoms and the structure of CuCP Lipo NPs. It is demonstrated that the synergistic strategy increases the intracellular lipid‐reactive oxides species, induces the occurrence of ferroptosis and apoptosis, and completely eradicates the tumors in vivo. Proteomics analysis further discloses the key involved proteins (including Tp53, HMOX1, Ptgs2, Tfrc, Slc11a2, Mgst2, Sod1, and several GST family members) and pathways (including apoptosis, ferroptosis, and ROS synthesis). Conclusively, this work develops a strategy based on one nanosystem to synergistically induce ferroptosis and apoptosis in vivo for tumor suppression, which holds great potential in the clinical translation for tumor therapy.