Fiber Optic Network Patents (Class 380/256)
  • Patent number: 7555127
    Abstract: In a quantum cryptography key distribution system for sharing a secret key between a transmitter and a receiver site, an unbalanced interferometer system in the transmitter site has a Mach-Zehnder interferometer switch with a phase modulator while the receiver site records photon arrival time slots. The system utilizes a whole of arrival photons in the receiver site and dispenses with any phase modulator in the receiver site. This system serves to improve a photon utilization efficiency.
    Type: Grant
    Filed: February 21, 2003
    Date of Patent: June 30, 2009
    Assignee: NEC Corporation
    Inventors: Yoshihiro Nambu, Toshiyuki Kambe
  • Publication number: 20090147955
    Abstract: A cryptography method using a quantum phenomenon, which performs a multi-staged polarization process between a transmitter and a receiver to prevent a third party from knowing the polarization value of a photon. A transmitter rotates a photon flux by arbitrary angle ? and transmits it to a receiver. The receiver rotates the received photon flux by arbitrary angle ? and transmits it to the transmitter. The transmitter rotates the received photon flux by the reverse angle ?? of an angle, by which the transmitter 10 rotated it, then rotates it by polarization corresponding to an information bit, and transmits it to the receiver which rotates the received photon flux by the reverse angle ?? of an angle, and measures the polarization of the photon flux corresponding to the information bit, and recovers the information bit transmitted by the transmitter. Cryptography information may be transmitted using a plurality of photon fluxes.
    Type: Application
    Filed: July 7, 2006
    Publication date: June 11, 2009
    Applicant: Paichai University Industry-Academic Cooperation Foundation
    Inventors: Chil-Min Kim, Won-Ho Kye, Young-Jai Park
  • Publication number: 20090150561
    Abstract: Methods for establishing modulator timing for a QKD system (100) having QKD stations (Alice, Bob) with respective modulators (MA, MB) are disclosed. The timing method includes exchanging non-quantum signals (P1, P2) between the two QKD stations and performing respective coarse timing adjustments by scanning the modulator timing domain with relatively coarse timing intervals (?T1C, ?T2C,) and wide (coarse) modulator voltage signals (W1C, W2C). Coarse timings (T1C, T2C) are established by observing a change in detector counts between single-photon detectors (32a, 32b) when modulation occurs in exchanged non-quantum signals. The method also includes performing a fine timing adjustment by scanning the modulator timing domain with respective fine timing intervals (?T1R, ?T2R) and respective relatively narrow modulator voltage signals (W1R, W2R), and again observing a change in detector counts for exchanged non-quantum signals.
    Type: Application
    Filed: February 24, 2005
    Publication date: June 11, 2009
    Inventor: Harry Vig
  • Publication number: 20090138709
    Abstract: An optical receiver comprising at least one processor and a memory including at least one of an encryption key or a decryption key and at least one of encryption microcode or decryption microcode that includes processor-executable instructions that, when executed by the at least one processor, cause the optical transceiver to perform the following: an act of performing an encryption or decryption operation on data received from a host computing system to thereby authenticate the optical transceiver.
    Type: Application
    Filed: November 26, 2008
    Publication date: May 28, 2009
    Applicant: FINISAR CORPORATION
    Inventors: Luke M. Ekkizogloy, Gerald L. Dybsetter, Jason Y. Miao
  • Patent number: 7539308
    Abstract: A system and method of detecting entangled photon pairs, each pair including a signal photon and an idler photon, is disclosed. Entangled photon pairs are provided having an entanglement time and an entanglement area selected to substantially increase an associated entangled two-photon cross-section of an associated target medium. The entangled photon pairs are also selected to have an energy distribution between the signal photon and the idler photon to substantially decrease an associated random two-photon absorption cross section of the target medium. The entangled photon pairs are directed to the target medium, and at least one entangled-photon pair being absorbed by the target medium is detected. The techniques for detecting entangled photons may be adapted to accommodate hiding information in entangled photons. That is, these techniques may be used for quantum steganography.
    Type: Grant
    Filed: May 21, 2004
    Date of Patent: May 26, 2009
    Assignee: General Dynamics Advanced Information Systems, Inc.
    Inventors: Ralph S. Conti, Kenneth A. Augustyn, Keith Kastella
  • Patent number: 7539314
    Abstract: Systems and methods for exchanging and processing encoded quantum signals in quantum key distribution (QKD) systems in real time. A stream of quantum signals is sent from Alice to Bob. Alice only encodes sets or “frames” of the streamed quantum signals based on receiving a “ready” message from Bob. This allows for Bob to finish processing the previous frame of data by allowing different bit buffers to fill and then be used for data processing. This approach results in gaps in between frames wherein quantum signals in the stream are sent unencoded and ignored by Bob. However, those quantum signals that are encoded for the given frame are efficiently processed, which on the whole is better than missing encoded quantum signals because Bob is not ready to receive and process them.
    Type: Grant
    Filed: August 14, 2006
    Date of Patent: May 26, 2009
    Assignee: MagiQ Technologies, Inc.
    Inventors: Audrius Berzanskis, Brandon Kwok, Harry Vig, Jonathan Young
  • Patent number: 7529373
    Abstract: A method of autocalibrating a quantum key distribution (QKD) system (200) is disclosed. The QKD system includes a laser ((202) that generates photon signals in response to a laser gating signal (S0) from a controller (248). The method includes first performing a laser gate scan (304) to establish the optimum arrival time (TMAX) of the laser gating signal corresponding to an optimum—e.g., a maximum number of photon counts (NMAX)—from a single-photon detector (SPD) unit (216) in the QKD system when exchanging photon signals between encoding stations (Alice and Bob) of the QKD system. Once the optimal laser gating signal arrival time (TMAX) is determined, the laser gate scan is terminated and a laser gate dither process (308) is initiated. The laser dither involves varying the arrival time (T) of the laser gating signal around the optimum value of the arrival time TMAX. The laser gate dither provides minor adjustments to the laser gating signal arrival time to ensure that the SPD unit produces an optimum (e.g.
    Type: Grant
    Filed: March 3, 2005
    Date of Patent: May 5, 2009
    Assignee: MagiQ Technologies, Inc.
    Inventors: Jonathan Young, Harry Vig, Michael J. Lagasse
  • Patent number: 7522724
    Abstract: A method of encrypting a transmission unit of a generalized scalable bit-stream includes, encrypting a plurality of logic units of the transmission unit using a unique encryption key for each logic unit, where the unique encryption keys for the transmission unit form a set of encryption keys. The method further includes providing a user with a subset of decryption information that corresponds to a subset of the encryption keys. The subset of the decryption information allows decryption of a subset of the logic units in the transmission unit up to a predetermined decryption level of the transmission unit.
    Type: Grant
    Filed: January 7, 2005
    Date of Patent: April 21, 2009
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Debargha Mukherjee
  • Publication number: 20090097650
    Abstract: Exemplary embodiments of detection and transmission arrangements are disclosed herein. For example, some of the disclosed embodiments comprise a splitter, a detector, first and second paths defined between the splitter and the detector, and a manipulation arrangement. In certain embodiments, the splitter is arranged to direct an incoming particle along the first or second path depending upon the value of a parameter of the incoming particle. In particular embodiments, the manipulation arrangement is located on at least one of the first and second paths, so that, if a particle in a superposition of values of the parameter impinges on the splitter and a wavefunction of the particle is directed along both the first and second paths, the manipulation arrangement will act on the wavefunction to allow interference, at or near the detector, between the portions of the wavefunction that were directed along the first and second paths.
    Type: Application
    Filed: December 16, 2005
    Publication date: April 16, 2009
    Inventor: Remi Oseri Cornwall
  • Patent number: 7515716
    Abstract: Systems and a methods are provided for reserving a rate at which cryptographic material is provided. A reservation request [700] for reserving the rate is sent from a secret bits consuming application [410] to a secret bit producing application [405]. The secret bits producing application [405] determines whether the reservation request can be satisfied. When the secret bits producing application determines that the reservation can be satisfied, the rate is reserved for the secret bits consuming application [410].
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: April 7, 2009
    Assignee: BBN Technologies Corp.
    Inventor: Brig Barnum Elliott
  • Patent number: 7512237
    Abstract: A multiplexing technique for optical communications used to create a pseudo-random communications signal in the optical domain such that only the sender and/or receiver can decode the signal. The multiplexing technique may include one or more information-bearing optical signals combined with one or more dynamic pseudo-randomly-generated optical signals to create a combined dynamic subcarrier multiplexed privacy-protected output signal. The information-bearing signal is protocol-independent and can be of mixed type, such as RF, analog, and/or digital. Only the receiver of the privacy-protected signal may decode the pseudo-random signal so as to disclose the information-bearing signal. The present invention may use dynamic subcarrier multiplexing selection based on standard digital encryption and the use of optical range time to ensure synchronization.
    Type: Grant
    Filed: October 26, 2004
    Date of Patent: March 31, 2009
    Assignee: Lockheed Martin Corporation
    Inventors: Howard J. Schantz, Rick C. Stevens, Steven H. Ernst
  • Patent number: 7502476
    Abstract: Systems and method of enhancing the security of a QKD system having operably coupled QKD stations (Alice, Bob) using correlated photon pulses (P1, P2) are disclosed. The method includes generating the correlated photon pulses at Alice and detecting one of the pulses (P2) to determine the number of photons in the other pulse (P1). Pulse P1 is then randomly modulated to form a modulated pulse P1?, which is transmitted to Bob. Bob then randomly modulates pulses P1? to form twice-modulated pulses P1?. Bob then detects pulses P1? at select timing slots that correspond to the expected arrival times of pulses P1?, as well as to the number of photons in pulse P1 (and thus in P1?). Bob then communicates with Alice to determine the number N1 of single-photon pulses P1? detected and the number N2 of multi-photon pulses P1? detected. A security parameter (SP) is defined based on the probabilities of detecting single-photon and multi-photon pulses.
    Type: Grant
    Filed: May 27, 2005
    Date of Patent: March 10, 2009
    Assignee: MagiQ Technologies, Inc.
    Inventors: Alexei Trifonov, Ekaterina Rogacheva
  • Patent number: 7492901
    Abstract: A single-photon generator includes an exciton generation part including therein a quantum dot, an excitation part for generating an exciton in the exciton generator part, a recombination control part for controlling recombination timing of the exciton in the exciton generation part, and an optical window provided in the exciton generation part so as to pass a single photon formed as a result of recombination of the exciton, wherein the recombination control part causes, in the exciton generation part, recombination of the excitons at longer intervals than a recombination lifetime of a exciton molecule.
    Type: Grant
    Filed: February 18, 2004
    Date of Patent: February 17, 2009
    Assignee: Fujitsu Limited
    Inventors: Kazuya Takemoto, Tatsuya Usuki, Motomu Takatsu
  • Publication number: 20090041243
    Abstract: A quantum encryption device comprises a faint laser light source for generating a photon serving as a qubit information carrier, three or more asymmetric Mach-Zehnder interference systems each formed by a photonic lightwave circuit, an optical transmission path for transmitting the photon, a photo detector, a device for recording sending data of a sender and observational data of a receiver, and a classic communication path for performing classic communication with a regular user.
    Type: Application
    Filed: March 16, 2007
    Publication date: February 12, 2009
    Applicant: NEC CORPORATION
    Inventor: Yoshihiro Nambu
  • Publication number: 20090028332
    Abstract: Data is encrypted onto an electromagnetic beam by providing an electromagnetic beam having a signal component having a modal state, wherein the signal component is susceptible to accumulation of a geometric phase, and a reference component, transmitted along a path over at least part of which the signal component accumulates a geometric phase by transformation of its modal state from a first to a second modal state, from the second to at least one further modal state, and then back to the first modal state; and modulating with the data the geometric phase so accumulated, by modulating the modal state transformations. Data is decrypted from a received electromagnetic beam by corresponding processing of the received electromagnetic beam and by comparing an overall phase of the signal component with an overall phase of the reference component so as to retrieve the modulation.
    Type: Application
    Filed: July 24, 2008
    Publication date: January 29, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Michael Charles Parker, Stuart Douglas Walker
  • Patent number: 7483535
    Abstract: A method of encrypting a transmission unit of a generalized scalable bit-stream includes, for each atom of the transmission unit, concatenating bit-stream segments that map to the atom to obtain data for each atom. The data for a logically first atom of the plurality of atoms of the multi-dimensional scalable representation is encrypted using an initialization input to produce an encryption output seed of the logically first atom and an encrypted logically first atom. In addition, the data of other atoms are encrypted to produce encrypted other atoms and an encryption output seed of each encrypted other atom. Encryption of a particular atom of the other atoms includes using encryption output seeds of adjacent causal atoms of the particular atom as an encryption input seed for encrypting the particular atom.
    Type: Grant
    Filed: September 15, 2004
    Date of Patent: January 27, 2009
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Debargha Mukherjee, Huisheng Wang
  • Publication number: 20090010435
    Abstract: An apparatus and method are disclosed for maximizing interference contrast in an interferometric quantum cryptography system to detect eavesdropping by utilizing a tunable emitter station in communications with a receiver station via a quantum communications channel and a “public” communications channel. The tunable emitter station tracks and compensates for interferometer drifts by adjusting the interference contrast of the QC system to minimize or eliminate inherent perturbations induced into key bit transmissions. Tuning of the photo emitter's output wavelength is accomplishable using temperature and/or drive current adjustment of the emitter's tunable optical subsystem.
    Type: Application
    Filed: July 7, 2007
    Publication date: January 8, 2009
    Inventor: Hugo Zbinden
  • Patent number: 7471793
    Abstract: A method and apparatus for secure distribution of cryptographic key information based on quantum cryptography is described. The apparatus incorporates or is used with a transmitter comprising a source of pairs of dim, depolarized light pulses together with a phase modulator and random number generator that are used to encode the pulse pairs with the binary key information by changing the relative phases of the pulses of some pairs. The apparatus incorporates a receiver comprising a polarization beam splitter, and a pair of interferometers and optical detectors. The invention overcomes problems associated with polarization evolution in quantum cryptography systems that incorporate a non-polarization-preserving optical channel (e.g. standard optical fiber).
    Type: Grant
    Filed: May 30, 2003
    Date of Patent: December 30, 2008
    Assignee: Corning Incorporated
    Inventors: Gabriele Bonfrate, Paul D. Townsend
  • Patent number: 7460669
    Abstract: An encoding method, decoding method and a communication method using single photons where information is directly encoded into each photon. In one embodiment at least two out of the three parameters of phases, polarization, and energy are used to encode information. In another embodiment, three or more non-orthogonal states with respect to each parameter are used. A further embodiment is also described which uses selective grouping of the results in order to more clearly detect the presence of an eavesdropper. Apparatus capable of performing the methods are also provided.
    Type: Grant
    Filed: October 25, 2001
    Date of Patent: December 2, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Clare Louise Foden, Andrew James Shields, David Mark Whittaker
  • Patent number: 7460670
    Abstract: A system (125) performs network management in a quantum cryptographic network (115). The system (125) monitors parameters associated with multiple links and multiple nodes of the quantum cryptographic network (115). The system (125) manages the multiple links and multiple nodes of the quantum cryptographic network (115) based on the monitored parameters.
    Type: Grant
    Filed: December 20, 2002
    Date of Patent: December 2, 2008
    Assignee: BBN Technologies Corp.
    Inventor: Brig Barnum Elliott
  • Publication number: 20080292102
    Abstract: A method and system for transmitting optical clock signals and quantum key signals on a single optical channel, and for reducing quantum bit error rate in a quantum key distribution system. The method includes receiving a multi-photon optical clock signal at an electro-optic switch at a first clock rate. The electro-optic switch may be configured for an interval defined by a second clock rate for generating a single photon quantum key signal. The multi-photon optical clock signal and the single photon quantum key signal may be combined such that the single optical channel transmits the single photon quantum key signal at a first interval and the multi-photon optical clock signal at a second interval. The quantum key signal may be transmitted from a transmitter at a first timing, and detected by a detector at a receiver. An output signal of the detector may be sampled at a second timing that is delayed relative to the first timing for reducing quantum bit error rate.
    Type: Application
    Filed: May 25, 2007
    Publication date: November 27, 2008
    Inventors: Shuoqin Wang, Daniel M. Zehnder, Jeffrey H. Hunt
  • Patent number: 7457416
    Abstract: Methods and systems are provided for distributing key information by securely transmitting light information in a network along a path comprised of a plurality of network devices and by using a key distribution center (KDC) connected with the network. Three or more user devices connected with the network are specified as constituting a secure communication group. Each user device sets up an end-to-end path to the KDC by configuring at least one of the network devices to direct light information along the path. Thereafter, a user key is established between each user device and the KDC, by sending light information using randomly selected quantum bases through the path. The KDC determines a shared secret key, and notifies each user device of the shared secret key by sending the result of a calculation based on the shared secret key and each user key through the network.
    Type: Grant
    Filed: July 17, 2002
    Date of Patent: November 25, 2008
    Assignee: BBN Technologies Corp.
    Inventor: Brig Barnum Elliott
  • Publication number: 20080285753
    Abstract: A system for passively scrambling and unscrambling a, pulse optical signal transmitted through a multi-mode optical fiber is provided. The system includes a scrambling unit connected between a signal receiving end of said transmission fiber and an optical signal source that includes an optical fiber which creates a differential delay between two groups of optical modes of the signal that is at least one bit period long such that said optical signal is passively scrambled, and an unscrambling unit connected to a signal transmitting end of said transmission fiber having an optical fiber that counteracts said differential delay between said two groups of optical modes of the signal such that said optical signal is passively unscrambled.
    Type: Application
    Filed: May 18, 2007
    Publication date: November 20, 2008
    Inventors: Shenping Li, Dmitri Vladislavovich Kuksenkov, Daniel Aloysius Nolan
  • Patent number: 7450854
    Abstract: A high-speed wireless LAN system is disclosed.
    Type: Grant
    Filed: June 3, 2004
    Date of Patent: November 11, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jong-Hun Lee, Yun-Je Oh, Do-In Choi
  • Patent number: 7450719
    Abstract: A Gigabit Ethernet-based passive optical network that can reliably transmit data is disclosed. The network includes an OLT for receiving a public key through a transmission medium, encrypting a secret key by means of the received public key, transmitting the encrypted secret key, encrypting data by means of the secret key, and transmitting the encrypted data, the OLT being located in a service provider-side. The network also includes an ONT for transmitting the public key to the OLT, receiving the secret key transmitted from the OLT, decrypting the secret key by means of a private key, receiving the data, and decrypting the received data by means of the decrypted the secret key. The public key is used for encrypting the secret key. The secret key is encrypted by means of the public key. The data is encrypted by the OLT by means of the secret key.
    Type: Grant
    Filed: January 16, 2004
    Date of Patent: November 11, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Hak-Phil Lee, Se-Kang Park, Whan-Jin Sung, Young-Seok Kim, Yun-Je Oh, Jun-Sung An, Tae-Sung Park, Su-Hyung Kim
  • Patent number: 7447386
    Abstract: A cascaded modulator system (20) and method for a QKD system (10) is disclosed. The modulator system includes to modulators (M1 and M2) optically coupled in series. A parallel shift register (50) generates two-bit (i.e., binary) voltages (L1, L2). These voltage levels are adjusted by respective voltage adjusters (30-1 and 30-2) to generate weighted voltages (V1, V2) that drive the respective modulators. An electronic delay element (40) that matches the optical delay between modulators provides for modulator timing (gating). The net modulation (MNET) imparted to an optical signal (60) is the sum of the modulations imparted by the modulators. The modulator system provides four possible net modulations based only on binary voltage signals. This makes for faster and more efficient modulation in QKD systems and related optical systems when compared to using quad-level voltage signals to drive a single modulator.
    Type: Grant
    Filed: February 23, 2006
    Date of Patent: November 4, 2008
    Assignee: Magiq Technologies, Inc
    Inventors: J. Howell Mitchell, Jr., Harry Vig, Michael J. LaGasse
  • Patent number: 7447312
    Abstract: The present invention describes an ultrafast secure data communication system that can link remote users to an encrypted database with holographic-stored data and a high security and ultrafast transfer rate.
    Type: Grant
    Filed: November 23, 2001
    Date of Patent: November 4, 2008
    Assignee: University of Connecticut
    Inventors: Bahram Javidi, Osamu Matoba
  • Publication number: 20080253568
    Abstract: A first header-attaching unit attaches to data of a low speed bit rate A, a header of the bit rate A. A second header-attaching unit attaches the header of the bit rate A to data of a high speed bit rate B. A combining unit combines outputs of the first and the second header-attaching units. A low speed scrambling unit performs a scrambling process on combined data by using a clock corresponding to the bit rate A. A high speed scrambling unit performs a scrambling process on the data of the bit rate B by using a clock corresponding to the bit rate B. During a timing corresponding to the bit rate A in the frame, a selector selects an output of the low speed scrambling unit. During a timing corresponding to the bit rate B in the frame, the selector selects an output of the high speed scrambling unit.
    Type: Application
    Filed: April 11, 2008
    Publication date: October 16, 2008
    Applicant: FUJITSU LIMITED
    Inventors: Yoshio Sakai, Kazuyuki Mori
  • Patent number: 7436961
    Abstract: A method of improving the security of a QKD system is disclosed. The method includes sending synchronization (“sync”) signals from a first QKD station to the second QKD station over a sync signal channel and recording data relating to the arrival times of the sync signals at the second QKD station. The method also includes processing the arrival time data to discern between extra signals in the sync signal channel that were not sent by the first QKD station over the sync channel, and sync signals that were sent by the first QKD station over the sync channel. The method also includes sending an alarm signal when it is determined that extra signals in the sync channel could be due to an attack on the QKD system.
    Type: Grant
    Filed: March 8, 2005
    Date of Patent: October 14, 2008
    Assignee: MagiQ Technologies, Inc.
    Inventors: Howell Mitchell, Harry Vig
  • Patent number: 7437081
    Abstract: A system and method for providing two-way communication of quantum signals, timing signals, and public data is provided. Generally, the system contains a first public data transceiver capable of transmitting and receiving public data in accordance with a predefined timing sequence, a first optical modulator/demodulator capable of transmitting and receiving timing signals in accordance with the predefined timing sequence, a first quantum transceiver capable of transmitting and receiving quantum signals in accordance with the predefined timing sequence, and a first controller connected to the first public data transceiver, the first optical modulator/demodulator, and the first quantum transceiver. The first controller is capable of controlling the transmission of the public data, the timing signals, and the quantum signals in accordance with the predefined timing sequence.
    Type: Grant
    Filed: November 1, 2004
    Date of Patent: October 14, 2008
    Assignee: Magiq Technologies, Inc
    Inventors: J. Howell Mitchell, Harry N. Vig, Anton Zavriyev, Alexei Trifonov
  • Patent number: 7430295
    Abstract: A method and system for distributing quantum cryptographic keys among a group of user devices through a switch connected to the user devices are provided. A switch [1000] establishes a connection between two user devices [405a, 405b] according to a schedule. A Quantum Key Distribution (QKD) session is established between the two user devices [405a, 405b] to facilitate sharing of secret key material between the two user devices. Connections and QKD sessions may be established for different pairs of the user devices.
    Type: Grant
    Filed: March 9, 2004
    Date of Patent: September 30, 2008
    Assignee: BBN Technologies Corp.
    Inventors: David Spencer Pearson, Brig Barnum Elliott
  • Patent number: 7418209
    Abstract: The invention provides, according to its various embodiments, a method for secure communication that involves encoding and transmitting an optical communications signal that is encoded based on a multi-dimensional encoding technique. The multi-dimensional encoding technique includes multiple security layers and varies multiple physical characteristics of a communications signal. The multi-dimensional encoding technique may include at least one or more of encoding a phase of an optical communications signal, encoding a polarization of an optical communications signal, and encoding a frequency of an optical communications signal, or any combination thereof. According to embodiments of the invention, the encoding and/or any decoding of the optical communications signal may be carried out using one or more of an optical phase shift coding, a polarization multiplexing, and a multi-wavelength control. Multi-dimensional encoding and decoding keys are provided.
    Type: Grant
    Filed: June 17, 2003
    Date of Patent: August 26, 2008
    Assignee: CeLight, Inc.
    Inventors: Aviv Salamon, Nadejda Reingand, Isaac Shpantzer, Michael Tseytlin
  • 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
  • Patent number: 7415111
    Abstract: An optical network unit and an optical line terminal which efficiently control the data receiving and dechurning processes in a passive optical network. In a churning parameter memory subsystem, a first memory bank stores churning parameters that are currently used, while a second memory bank stores updates made to the churning parameters. Under the control of the churning parameter memory subsystem, those first and second memory banks change their roles with each other at a churning key updating time point. A data dechurning unit receives a data stream consisting of a plurality of frames and dechurns the information contained in the data stream, according to the stored churning parameters. When an update is done to the parameters in a certain frame, the data dechurning unit makes the update effective at the next frame, thus starting data dechurning operations from the next frame.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: August 19, 2008
    Assignee: Fujitsu Limited
    Inventors: Takashi Monzawa, Kenji Miura, Tamotsu Matsuo, Hideki Shiono, Yoshimi Toyoda, Toshinori Koyanagi, Setsuo Abiru, Jun Asato, Shinichi Fujiyoshi, Kazuhiro Uchida, Kazuya Ryu, Katsuhiko Hirashima, Tateo Shimaru, Mitsuharu Wakayoshi, Toshiyuki Sakai
  • Patent number: 7406173
    Abstract: A quantum communication apparatus is used in operations to generate entanglement between the two physical system ensembles and operations to extend the distance between entangled ensembles by connecting pairs of entangled ensembles. The apparatus uses only passive elements without any actuating parts, active devices having no mechanically actuating parts, such as an electro-optical device capable of ultrahigh-speed operation, and a laser source capable of generating high-speed pulse trains or a continuous wave laser source. The apparatus can rapidly execute light irradiation necessary for entanglement generation and connection, and detection of a generated photon at the needed sites within a decoherence time of the physical system.
    Type: Grant
    Filed: October 2, 2003
    Date of Patent: July 29, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kouichi Ichimura, Noritsugu Shiokawa
  • Publication number: 20080175385
    Abstract: A QKD system having QKD link redundancy between two sites, with the system having only one QKD station at each site, and with two or more QKD links operably coupled to the QKD stations. The QKD stations have respective optical switches that are optically coupled to both QKD links and that are controlled by respective controllers in each of the QKD stations. If one of the QKD links fails or has trouble transmitting optical signals, the QKD switches are switched so that the optical path between the QKD stations uses the remaining QKD link. This arrangement requires only two QKD stations rather than the four QKD stations as presently taught in the prior art.
    Type: Application
    Filed: January 16, 2008
    Publication date: July 24, 2008
    Inventors: Keun Lee, Audrius Berzanskis
  • Patent number: 7403623
    Abstract: One aspect of the present invention is related to a quantum cryptographic scheme comprising at least one sending unit including a physical means of encoding and distributing a raw key in the quadrature components of quantum coherent states that are continuously modulated in phase and amplitude, at least one receiving unit containing a physical means of performing homodyne detection of the quantum coherent states in order to measure the quadrature components of the states, a quantum channel for connecting the sending unit to the receiving unit, a two-way authenticated public channel for transmitting non-secret messages between the sending unit and the receiving unit, a quantum key distribution protocol ensuring that the information tapped by a potential eavesdropper can be estimated from the quantum channel parameters, and a direct or reverse reconciliation protocol that converts the raw continuous data into a common binary key.
    Type: Grant
    Filed: July 7, 2003
    Date of Patent: July 22, 2008
    Assignees: Universite Libre de Bruxelles, Centre National de la Recherche Scientifique
    Inventors: Nicolas Cerf, Rosa Brouri-Tualle, Philippe Grangier, Frédéric Grosshans, Gilles Van Assche, Jérôme Wenger
  • Patent number: 7400724
    Abstract: The present invention relates to a quantum cryptography system for the secure key generation, especially with signal sources and analysis channels. The signal sources are arranged spatially separated in such a manner that the wave fronts of light signals emitted by them superimpose partially at the input of the quantum channel. The analysis channels are arranged in such a manner that the wave front of the light signals coming from the quantum channel are split up spatially and at least two of the parts are analyzed in a quantum mechanical state.
    Type: Grant
    Filed: April 5, 2002
    Date of Patent: July 15, 2008
    Assignee: Ludwig-Maximilians-Universitat Muchen
    Inventors: Harald Weinfurther, Christian Kurtsiefer
  • Patent number: 7391867
    Abstract: Systems and methods for graphically displaying statistical information relating to the operation of a quantum key distribution (QKD) system. The method includes exchanging quantum photons between first and second QKD stations for each combination of modulator states, collecting data on the number of quantum photon counts obtained in each of two detectors for each modulator state combination, defining a statistical region for each modulator state combination based on the collected data, and displaying the statistical regions on a graph having indicia indicating ideal locations for the statistical regions. The method also optionally includes adjusting the QKD system based on the graphically displayed information to optimize system performance.
    Type: Grant
    Filed: April 22, 2004
    Date of Patent: June 24, 2008
    Assignee: MagiQ Technologies, Inc.
    Inventor: Harry Vig
  • Publication number: 20080144823
    Abstract: A wavelength demultiplexer demultiplexes a wavelength multiplexed incident photon pulse string based on wavelengths of the photons in the photon pulse string. Each of a plurality of photon detectors detects a photon that is demultiplexed by the wavelength demultiplexer and outputs a signal based on detected photon, and a bias applying unit applies a gate pulse as a bias voltage to at least some of the photon detectors to match an incidence timing of an output light of the wavelength demultiplexer to the photon detectors. A data processor converts the signals from the photon detectors into time series signals.
    Type: Application
    Filed: July 12, 2004
    Publication date: June 19, 2008
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Jun'ichi Abe, Katsuhiro Shimizu, Toshio Hasegawa, Tsuyoshi Nishioka, Hirokazu Ishizuka
  • Publication number: 20080137858
    Abstract: Systems and methods that allow for transmitting qubits and classical signal over the same channel of an optical telecommunications network that includes an optical fiber. The method includes sending the qubits of wavelength ?S over a quantum optical path that includes the optical fiber during a time interval ?T0 when there are no classical optical signals of wavelength ?S traveling over the optical fiber. The method also includes sending the classical signals over a classical optical path that includes the optical fiber, wherein the classical signals are sent outside of the time interval ?T0 to avoid interfering with the qubit transmission. Systems and methods for using the present invention to form quantum key banks for encrypting classical signals sent over the optical telecommunications network are also disclosed.
    Type: Application
    Filed: December 4, 2007
    Publication date: June 12, 2008
    Inventors: Robert Gelfond, A. Craig Beal, Audrius Berzanskis, Joseph E. Gortych
  • Publication number: 20080130887
    Abstract: A secure data communication system configuration to encrypt the data to be transmitted within the random phase fluctuations of the field spectrum of a low temporal coherence source and to decrypt the data at the receiver through an autocorrelation technique. The optical field encryption technique disclosed herein uses a dual interferometer and has the advantages of being realisable with current technology allowing high data rates and opaqueness to an unwanted observer on the system upon which data is being transferred.
    Type: Application
    Filed: March 10, 2005
    Publication date: June 5, 2008
    Inventors: Andrew M. Harvey, Colin Fraser
  • Publication number: 20080130888
    Abstract: Methods and apparatus for generating coherent optical pulses (P1?, P2?) in a quantum key distribution (QKD) station (Alice-N) of a QKD system (10) without using an optical fiber interferometer (12) are disclosed. The method includes generating a continuous wave (CW) beam of coherent radiation (R) having a coherence length LC and modulating the CW beam within the coherence length. The invention obviates the need for an interferometer loop to form multiple optical pulses from a single optical pulse, thereby obviating the need for thermal stabilization of the interferometer loop at the QKD station Alice-N.
    Type: Application
    Filed: September 12, 2005
    Publication date: June 5, 2008
    Inventors: Alexei Trifonov, Darius Subacius
  • Patent number: 7369662
    Abstract: A method and an arrangement maintain end-to-end synchronization on a telecommunications connection transmitting data in frames substantially in real time and using synchronized end-to-end encryption, wherein at least a part of the telecommunications connection is a packet-switched connection, in which case the reproduction delay of the data to be transmitted can be increased by adding one or more extra frames to the frame string being transmitted, wherein the arrangement defines, based on the number of received frames, an initialization vector value corresponding to a frame received at the receiving end of the telecommunications connection and used in decrypting the frame, adjusts the reproduction delay to mark the frame to be added to increase the reproduction delay as an extra frame, and defines the initialization vector value to count only the frames not marked as extra frames in the number of received frames.
    Type: Grant
    Filed: November 27, 2001
    Date of Patent: May 6, 2008
    Assignee: Eads Secure Networks Oy
    Inventors: Rasmus Relander, Raimo Kantola
  • Patent number: 7359513
    Abstract: An apparatus and method for implementing a quantum cryptography system encoding bit values on approximations of elementary quantum systems with provable and absolute security against photon number splitting attacks. The emitter encodes the bit values onto pairs of non-orthogonal states belonging to at least two sets, and such that there does not exist a single quantum operation allowing to reduce the overlap of the states in all the sets simultaneously.
    Type: Grant
    Filed: November 12, 2003
    Date of Patent: April 15, 2008
    Assignee: Universite de Geneve
    Inventors: Nicolas Gisin, Antonio Acin, Valerio Scarani, Grégoire Ribordy
  • Patent number: 7359514
    Abstract: A narrow-band single-photon source (10) is disclosed, along with a QKD system (200) using same. The single-photon source is based on spontaneous parametric downconversion that generates signal and idler photons (PS and PI) as an entangled photon pair. Narrow-band signal photons are generated by selectively narrow-band-filtering the idler photons. This results in a non-local filtering of the signal photons due to the time-energy entanglement of the photon pair. Subsequent detection of the filtered idler photon establishes the narrow-band signal photon. The narrow-band single-photon source is particularly useful in a QKD system, wherein the narrow-band signal photons are used as quantum signals to mitigate the adverse effect of chromatic dispersion on QKD system performance.
    Type: Grant
    Filed: October 27, 2005
    Date of Patent: April 15, 2008
    Assignee: MagiQ Technologies, Inc.
    Inventors: Alexei Trifonov, Anton Zavriyev
  • Patent number: 7349537
    Abstract: One embodiment of the present invention provides a system that decrypts downstream data in an Ethernet passive optical network (EPON). During operation, the system receives a data frame which is encrypted based on a remote input block and a session key, wherein the remote input block is constructed based on a remote cipher counter and a remote block counter. The system adjusts a local cipher counter based on a received checksum located in a preamble of the data frame, wherein the local cipher counter is substantially synchronized with the remote cipher counter. In addition, the system truncates the local cipher counter by discarding n least significant bits thereof. The system then constructs a local input block based on the truncated cipher counter and a local block counter for the received data frame. Next, the system decrypts the data frame based on the local input block and the session key.
    Type: Grant
    Filed: March 10, 2005
    Date of Patent: March 25, 2008
    Assignee: Teknovus, Inc.
    Inventors: Glen Kramer, Lawrence D. Davis, Edward W. Boyd, Ryan E. Hirth, Ngo Thahn Ho
  • Patent number: 7333611
    Abstract: A method and system for achieving the cryptographic objectives of data encryption and/or key expansion/generation by utilizing a short, shared, secret seed key between two parties that is extended to a long extended key which, in turn, is used to select one of many possible quantum and/or classical signal sets. The signal strength of each signal in the signal set is adjusted in accordance with the number of signal sets to obtain the necessary security level. The system operates with whatever signal quantum noise and other system noises are present while preserving security of the cryptographic system. The signal quantum noise and system noises protect both the data and the key from attackers.
    Type: Grant
    Filed: September 29, 2003
    Date of Patent: February 19, 2008
    Assignee: Northwestern University
    Inventors: Horace P. Yuen, Prem Kumar, Geraldo A. Barbosa
  • Patent number: 7333612
    Abstract: Methods and apparatus are provided for improving message-based security in a Fibre Channel network. More specifically, the present invention relates to methods and apparatus for providing confidentiality for Fibre Channel control messages encapsulated within Common Transport Information Units. Control messages transported with the Fibre Channel Common Transport protocol, and passed between Fibre Channel network entities, can be encrypted providing confidentiality combined with data origin authentication, integrity and anti-replay protection provided by existing Fibre Channel security mechanisms.
    Type: Grant
    Filed: March 19, 2004
    Date of Patent: February 19, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Fabio R. Maino, Claudio DeSanti
  • Patent number: 7330550
    Abstract: A cryptographic system includes: a) a light source for generating an excitation light signal; b) a spatial light modulator for encoding the excitation light signal with data; c) a wavelength dispersive element for transforming the excitation light signal into a spectral encoded light signal characterized by relative peak intensities at specific wavelengths; d) an optical detector for generating an information output signal in response to receiving an optical input signal, wherein the information output signal represents spectral and intensity characteristics of the optical input signal; and e) a processor for validating the information output signal if differences between representations of the optical input signal, and representations of the spectral encoded light signal are within predetermined limits.
    Type: Grant
    Filed: February 19, 2003
    Date of Patent: February 12, 2008
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Shikik T. Johnson, Stephen D. Russell