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- 1. Coexistence of High-Bit-Rate QKD and Data on Optical Fiber
- 2. Quantum Cryptography: Cryptographic technique based on the laws of physics. Transmits photons(qubits) instead of electrical signals(bits). In theory, it achieves totally secure communications. Once photons have been observed, they are irrevocably changed. Quantum key distribution is the most well known example.
- 3. Quantum key distribution (QKD): Two distinct channels. Quantum key channel. Public data channel.
- 4. BB84 Protocol:
- 5. Eavesdropping detection: Error rate < E max No eavesdropping Error rate > E max Eavesdropping or the channel is noisy. Alice and Bob should then discard the whole key and start over.
- 6. SO what is the state of the art in quantum cryptography?
- 7. Current limitation: Quantum keys are faint and delicate. They require dedicated expensive dark fibers . Trying to use such low-level signals over 'lit fiber' has been rather like trying to see the stars whilst staring at the Sun Quantum and data signals have extreme contrast in their intensities. So plucking the quantum key photons out of the fibre is impossible.
- 8. Toshiba research: Transmit the quantum photons and data signals at different wavelengths So signals won’t clash. Develop detectors catch just one photon at a time. Gate opens for just a tenth of a billionth of a second. Quantum key signal photons arrive, one by one.
- 9. Results: Transmit binary data at 1Gbps in both directions. Perform QKD at 500Kbps at the same time over a 90km. This is 50,000 times faster than the previous best QKD.
- 10. References: http://www.techrepublic.com/blog/security/howquantum-cryptography-works-and-by-the-way-itsbreakable/7762 http://www.bbc.co.uk/news/science-environment13940928 http://www.extremetech.com/computing/142438qubits-and-binary-data-successfully-squirted-downthe-same-fiber-at-the-same-time-here-comesquantum-cryptography http://www.authorstream.com/Presentation/aSGuest131 522-1380275-quantum-cryptography/
- 11. THANKS

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