Secured wireless communications

Patent metadata

Field	Value
Publication number	US-9641326-B2
Application number	US-201214402677-A
Country	US
Kind code	B2
Filing date	May 31, 2012
Priority date	May 31, 2012
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

The disclosure relates to secured wireless communications. A sender device emits randomly photons in a first polarization, a second polarization and a third polarization without aligning a polarization system in a plane perpendicular to the first and second polarizations with a recipient device. The recipient device is adapted for detection of events in association with six polarizations. The recipient device selects randomly polarization basis for measurement of the received photons. Information of detected events in association with three basis is communicated to the sender device. The information from the recipient device and information stored in the sender device is processed to determine events where same polarization basis was used by the sender device and the recipient device.

First claim

The invention claimed is:

1. A method comprising:
emitting from a sender device randomly photons in a first polarization, a second polarization and a third polarization without aligning a polarization system in a plane perpendicular to the first and second polarizations with a recipient device, the recipient device being adapted for detection of photons in association with six polarizations,
storing in a memory of the sender device a bit value and a polarization corresponding to each of the emitted photons,
receiving information of detected photons from the recipient device in the absence of having sent to the recipient device information about the polarizations used for the emitted photons,
determining photons where the same polarization basis consisting of the third polarization and its opposite was used by the sender device and the recipient device and the bit values match between the stored bit value and the received detected photon,
error correcting the determined photons using the received information and the stored bit values and polarizations; and
constructing a cryptographic key using only the bit values remaining after the error correcting and storing said key in the memory for use with the recipient device.

2. The method according to claim 1 , comprising
determining use of a different polarization basis by the sender device and the recipient device for a photon, and
communicating information of sender basis and bit values in response to determination of at least one photon with the different polarization basis.

3. The method according to claim 1 , comprising emitting a single photon per pulse in each of the six polarizations.

4. A method comprising
receiving at a recipient device photons from a sender device via an optical channel emitted on a first polarization, a second polarization and a third polarization without aligning a polarization system in a plane perpendicular to the first and second polarizations with the sender device,
selecting randomly polarization basis for measurement of received photons for detection of photons on six polarizations,
sending information of detected photons in association with three polarization bases to the sender device,
receiving information from the sender device of photons where the same polarization basis was used by the sender device and the recipient device;
constructing a raw key using only bit values corresponding to the detected photons associated with the same polarization basis received from the sender device;
error correcting the raw key; and
constructing a cryptographic key using only the bit values remaining after the error correcting and storing said key in a memory of the recipient device for use with the sender device.

5. An apparatus comprising: at least one processor; and at least one memory including computer program instructions, wherein the at least one memory and computer program instructions are configured to, with the at least one processor, cause the apparatus at least to:
cause emission of photons using randomly a first polarization, a second polarization and a third polarization for sending the photons without aligning a polarization system in a plane perpendicular to the first and second polarizations with a recipient device, the recipient device being adapted for detection of photons in association six polarizations,
store in the at least one memory a bit value and a polarization corresponding to each of the emitted photons,
receive information of detected photons from the recipient device in the absence of having sent to the recipient device information about the polarizations used for the emitted photons,
determine events where the same polarization basis consisting of the third polarization and its opposite was used by the sender device and the recipient device and the bit values match between the stored bit value and the received detected photon,
error correct the determined photons using the received information and the stored bit values and polarizations; and
constructing a cryptographic key using only the bit values remaining after the error correcting and storing said key in the at least one memory for use with the recipient device.

6. The apparatus according to claim 5 , wherein the apparatus is further caused to determine use of a different polarization basis by the sender device and the recipient device for a photon, and cause communication of information of sender basis and bit values in response to determination of at least one photon with the different polarization basis.

7. The apparatus according to claim 5 , wherein the apparatus is further caused to use synchronized timing for the photons.

8. The apparatus according to claim 5 , wherein the apparatus further comprises a quantum random number generator for providing randomness for the basis selection.

9. The apparatus according to claim 5 , wherein the apparatus is further caused to
correlate a time synchronized record of photons detected by the recipient device with a record of photons maintained by the sender device, and
sift the information to obtain raw keys based on bits in times when the same basis was used by the sender and recipient devices.

10. A recipient device comprising at least one processor; and at least one memory including compute program instructions, wherein the at least one memory and computer program instructions are configured to, with the at least one processor, cause the recipient device at least to:
randomly select polarization basis for measurement of photons received from a sender device emitted on a first polarization, a second polarization and a third polarization without aligning a polarization system in a plane perpendicular to the first and second polarizations, and
detect photons in association with said six polarizations,
cause sending of information of detected photons in association with three polarization bases to the sender device,
receive information from the sender device of photons where the same polarization basis was used by the sender device and the recipient device;
construct a raw key using only bit values corresponding to the detected photons associated with the same polarization basis received from the sender device;
error correct the raw key; and
construct a cryptographic key using only the bit values remaining after the error correcting and store said key in a memory of the recipient device for use with the sender device.

Assignees

• Wabnig Joachim
• Niskanen Antti
• Li Hongwei
• Bitauld David
• Nokia Technologies Oy

Inventors

• Wabnig Joachim
• Niskanen Antti
• Li Hongwei
• Bitauld David

Classifications

• H04L2209/24

  Key scheduling, i.e. generating round keys or sub-keys for block encryption · CPC title

• H04B10/70

  Photonic quantum communication · CPC title

• H04L9/14

  using a plurality of keys or algorithms · CPC title

• H04L2209/80

  Wireless · CPC title

• H04L9/0858 Primary

  Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding · CPC title