Patents by Inventor Hoi-Kwong Lo

Hoi-Kwong Lo has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9602220
    Abstract: The disclosure concerns quantum repeater network system that does not need any matter qubit. According to the quantum repeater network system for performing quantum communication between one transmitter/receiver and the other transmitter/receiver via transmission repeaters and reception repeaters, each of the transmission repeaters prepares quantum systems in an irreducibly entangled state, each of the quantum systems being associated with a reception repeater as a transmission destination, and transmits, to the associated reception repeater, each of the quantum systems in the irreducibly entangled state together with a quantum system entangled with the quantum system.
    Type: Grant
    Filed: June 11, 2014
    Date of Patent: March 21, 2017
    Assignees: Nippon Telegraph and Telephone Corporation, The Governing Council of the University of Toronto
    Inventors: Koji Azuma, Kiyoshi Tamaki, Hoi-Kwong Lo
  • Publication number: 20140363174
    Abstract: Provided is a quantum repeater network system that does not need any matter qubit. According to the quantum repeater network system for performing quantum communication between one transmitter/receiver and the other transmitter/receiver via transmission repeaters and reception repeaters, each of the transmission repeaters prepares quantum systems in an irreducibly entangled state, each of said quantum systems being associated with a reception repeater as a transmission destination, and transmits, to the associated reception repeater, each of the quantum systems in the irreducibly entangled state together with a quantum system entangled with the quantum system.
    Type: Application
    Filed: June 11, 2014
    Publication date: December 11, 2014
    Inventors: Koji Azuma, Kiyoshi Tamaki, Hoi-Kwong Lo
  • Patent number: 8554814
    Abstract: Systems and methods for generating a random signal, based on quantum noise in the phase of two or more input signals. The generated output random signal has random variation in its intensity based on the quantum noise in the phases of the input signals.
    Type: Grant
    Filed: August 20, 2010
    Date of Patent: October 8, 2013
    Assignee: The Governing Council of The University of Toronto
    Inventors: Bing Qi, Hoi-Kwong Lo, Li Qian
  • Publication number: 20120045053
    Abstract: Systems and methods for generating a random signal, based on quantum noise in the phase of two or more input signals. The generated output random signal has random variation in its intensity based on the quantum noise in the phases of the input signals.
    Type: Application
    Filed: August 20, 2010
    Publication date: February 23, 2012
    Inventors: Bing QI, Hoi-Kwong LO, Li QIAN
  • Patent number: 7570767
    Abstract: An apparatus (1) and method for decoupling error correction from privacy amplification in a quantum key distribution (QKD 100) system includes two or more computer systems (102, 108) linked by quantum and classical channels (120, 122) where each computer system determines a generalized error syndrome associated with quantum communication between the systems, encrypts the generalized error syndrome using a sequence of values, and communicates the encrypted generalized error syndrome via a classical channel (128) to the other system, which uses the encrypted generalized error syndromes to compute error correction for the quantum transmission.
    Type: Grant
    Filed: December 20, 2002
    Date of Patent: August 4, 2009
    Assignee: MagiQ Technologies, Inc.
    Inventor: Hoi Kwong Lo
  • Patent number: 7415114
    Abstract: This invention provides a quantum key distribution (QKD) system and method for determining initial quantum keys (QKs), including an initial QKA (220) and an initial QKB (230), determining an initial QKA value of a first function applied to said initial QKA, wherein a value of said first function depends upon values of specified information unit of a QK, including bit i (210), determining an initial QKB value of said first function applied to said initial QKB; and forming a revised QKA by depending a value of an information unit of said revised QKA on a value of information unit i of said initial QKA, if said initial QKA value equals said initial QKB value.
    Type: Grant
    Filed: April 30, 2002
    Date of Patent: August 19, 2008
    Assignee: MagiQ Technologies, Inc.
    Inventors: Hoi Kwong Lo, Daniel Gottesman
  • Publication number: 20070127932
    Abstract: The present invention provides an optical phase modulation method using optical frequency shift devices. By accurately controlling the frequency shift, the phase delay experienced by the light signal through an optical medium (fibre, free space, vacuum, or other) can be controlled with high resolution. Hence, phase change can be achieved through frequency change. This technique can be applied to a wide range of applications whenever phase modulation is needed, such as in various phase-shifted keying techniques in optical communications, and in optical metrology. The disclosed phase modulation method can also be used as a phase encoding technique in quantum key distribution.
    Type: Application
    Filed: December 1, 2006
    Publication date: June 7, 2007
    Inventors: Bing Qi, Li Qian, Hoi-Kwong Lo, Yi Zhao
  • Patent number: 7197523
    Abstract: Apparatus for and methods of random number generation are disclosed, wherein a detector receives a group of n light pulses having single-photon intensity levels. Each of the n light pulses has a probability of less than one to produce a successful detection event at its time of arrival at the detector, and the detector is adapted to detect only one of the n pulses in the group. This single detection per group is thus a discrete random event that occurs only during one of n fixed time slots. The random event occurring during one of n timeslots is converted into a corresponding random integer from 1 to n. A series of such random numbers is generated by using a plurality of groups of n light pulses.
    Type: Grant
    Filed: May 3, 2002
    Date of Patent: March 27, 2007
    Assignee: Magiq Technologies, Inc.
    Inventors: Norbert Lutkenhaus, Jayson L. Cohen, Hoi-Kwong Lo
  • Patent number: 7069439
    Abstract: Computing apparatus comprises a memory means storing the instructions of a secure process and an authentication process; a processing means arranged to control the operation of the computing apparatus including by executing the secure process and the authentication process; a user interface means arranged to receive user input and return to the user input; and an interface means for receiving a removable primary token and communication with the token. The token comprises a body supporting a token interface for communicating with the interface means, a token processor; and a token memory adapted to store token data including information for identifying the token and auxiliary token information identifying one or more authorized auxiliary tokens.
    Type: Grant
    Filed: March 3, 2000
    Date of Patent: June 27, 2006
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Liqun Chen, Hoi-Kwong Lo, David Chan
  • Publication number: 20040190719
    Abstract: An apparatus (1) and method for decoupling error correction from privacy amplification in a quantum key distribution (QKD 100) system includes two or more computer systems (102, 108) linked by quantum and classical channels (120, 122) where each computer system determines a generalized error syndrome associated with quantum communication between the systems, encrypts the generalized error syndrome using a sequence of values, and communicates the encrypted generalized error syndrome via a classical channel (128) to the other system, which uses the encrypted generalized error syndromes to compute error correction for the quantum transmission.
    Type: Application
    Filed: April 8, 2004
    Publication date: September 30, 2004
    Inventor: Hoi Kwong Lo
  • Publication number: 20040141618
    Abstract: This invention provides a quantum key distribution (QKD) system and method for determining initial quantum keys (QKs), including an initial QKA (220) and an initial QKB (230), determining an initial QKA value of a first function applied to said initial QKA, wherein a value of said first function depends upon values of specified information unit of a QK, including bit i (210), determining an initial QKB value of said first function applied to said initial QKB; and forming a revised QKA by depending a value of an information unit of said revised QKA on a value of information unit i of said initial QKA, if said initial QKA value equals said initial QKB value.
    Type: Application
    Filed: March 1, 2004
    Publication date: July 22, 2004
    Inventors: Hoi Kwong Lo, Daniel Gottesman
  • Publication number: 20040139132
    Abstract: In an apparatus and methods of random number generation, a detector (60) receives a plurality of groups of n light pulses (50), which an attenuator (40) typically dims to single-photon intensity levels. Each of the n light pulses has a probability less than one to produce a successful detection event at its time of arrival at the detector, but the detector detects only one of the n pulses per group. This single detection per group is thus a discrete random event. This detection even can occur only during one of n fixed timeslots during which a pulse may arrive at the detector. The method of the invention converts the random event at one of n timeslots into a random integer from 1 to n. The expected arrival time of the first pulse of the group becomes a timing reference with which to start a timer (90) and define the define the timeslots electronically.
    Type: Application
    Filed: September 22, 2003
    Publication date: July 15, 2004
    Inventors: Norbert Lutkenhaus, Jayson L . Cohen, Hoi-Kwong Lo
  • Patent number: 5732139
    Abstract: A secure method for distributing a random cryptographic key with reduced data loss. Traditional quantum key distribution systems employ similar probabilities for the different communication modes and thus reject at least half of the transmitted data. The invention substantially reduces the amount of discarded data (those that are encoded and decoded in different communication modes e.g. using different operators) in quantum key distribution without compromising security by using significantly different probabilities for the different communication modes. Data is separated into various sets according to the actual operators used in the encoding and decoding process and the error rate for each set is determined individually. The invention increases the key distribution rate of the BB84 key distribution scheme proposed by Bennett and Brassard in 1984. Using the invention, the key distribution rate increases with the number of quantum signals transmitted and can be doubled asymptotically.
    Type: Grant
    Filed: August 26, 1996
    Date of Patent: March 24, 1998
    Inventors: Hoi-Kwong Lo, Hoi Fung Chau