Abstract: A quantum key distribution (QKD) receiver is provided for communicating with a transmitter that produces a plurality of entangled photon qubit pairs to send one qubit from each pair randomly alternating between basis states. The receiver includes a first polarized beam splitter, an orthogonal pair of photon detectors, a weak measurement apparatus, a broadcaster, an error rate estimator, and a post-processor. The first splitter receives the one qubit for passage or reflection. The photon detector pair measures the one qubit from passage or reflection. The apparatus performs a weak measurement on the one qubit and includes an impedance device to induce time delay, a pair of mirrors flanking the impedance device, and second and third polarized beam splitters for alternatively passing the one qubit to each other and to the pair of mirrors. The broadcaster for sending weak measurement results from the detectors to the transmitter.

Abstract: A communication process is provided for sending a qubit message between Alice and Bob using a quantum channel for obviating a faked-state attack by Eve. The qubit message is composed of ensemble bits and transmitted as a plurality of photons into the quantum channel. Each photon has a corresponding bit value. The process includes: Alice preparing three uniformly random bit strings each of length 4N to produce strings R (raw key), P (bit basis) and U (unitary operation), and Bob preparing two uniformly random bit strings of the same length to produce strings M (bit basis) and V (unitary operation). Alice broadcasts P, applies her unitary operation and records a first weak measurement to the photons for transmission. Meanwhile Bob broadcasts M, applies his unitary operation and records both a second weak measurement and a strong measurement to the photons.

Abstract: A method is provided for distributing a random list of binary values between first and second parties. The method includes sending photons from the second party into an interferometer at a first beam splitter; performing a first weak measurement on photons as a first pointer result into a first time-ordered list for photons; performing a second weak measurement by the first party on photons that pass through a second beam splitter as being a second pointer result into a second time-ordered list; recording identification for first and second detectors that the photons arrive via a third beam splitter as respective first and second detector registrations for collecting in a third time-ordered list as respective first and second detection lists; determining first and second averages of the respective first and second detection lists; and comparing the averages to verify existence of a non-trivial difference that indicates secure communication status of the element's binary value.

Abstract: A method is provided for distributing a random list of binary values between first and second parties. The method includes sending photons from the second party into an interferometer at a first beam splitter; performing a first weak measurement on photons as a first pointer result into a first time-ordered list for photons; performing a second weak measurement by the first party on photons that pass through a second beam splitter as being a second pointer result into a second time-ordered list; recording identification for first and second detectors that the photons arrive via a third beam splitter as respective first and second detector registrations for collecting in a third time-ordered list as respective first and second detection lists; determining first and second averages of the respective first and second detection lists; and comparing the averages to verify existence of a non-trivial difference that indicates secure communication status of the element's binary value.