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التحقق عمليا من بروتوكول البينغ بونغ
Author name:
علاء جبار جمعة
Supervisor name:
شيلان خسرو توفيق
General topic:
Laser Science
Specific topic:
Laser Applications in Electronics and Communications Engineering
Degree:
Master
University:
University of Baghdad - Laser Institute For Postgraduate Studies
Language:
English
University location:
Baghdad
First pages:
29T198 - p.pdf
Abstract:
Quantum cryptography uses basic laws of quantum physics to guarantee secure key exchange. The key can be used with unprecedented confidence in any classic cryptographic protocol, where it increases the security to the maximum achievable value. The goal of this work is to encrypt the message directly without need to generate the secure key by using the modified Ping - Pong Protocol. A quantum cryptography system based on Modified Ping - Pong Protocol was designed and implemented for the first time. A polarization - entangled photons were generated by a source using PPKTP crystal inside a polarization Sagnac interferometer at telecom wavelength 1550 nm and a fiber length of 15 Km. In this experiment, Bob prepares entangled photons, sends one photon to Alice by optical fiber to perform one out of four operators according to the message. The modulated photon is sent back to Bob. Then the Bell’s state measurement is applied to extract the message according to the Alice’s coding. The HOM - dip of the two - photon interference was verified to guarantee perfect system performance. The final results showed the switching between the Bell’s states, |????+⟩ and |????−⟩ as the phase of the phase modulator was changed by Alice achieving an acceptable coincidence count of about 625 counts per 30s. These results proves also two photon interference needed to test Bell’s enquality.
