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Quantum Oblivious Transfer: Difference between revisions
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==Outline== | ==Outline== | ||
The | The oblivious transfer protocol occurs in two phases. The preparation phase, followed by the Computation phase. | ||
The | |||
===Preparation phase=== | ===Preparation phase=== | ||
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===Computation phase=== | ===Computation phase=== | ||
The sender sends a random sequence of faint pulses of the four canonical polarizations from the standard basis and the | The sender sends a random sequence of faint pulses of the four canonical polarizations from the standard basis and the Hadamard basis. | ||
The receiver randomly decides for each pulse whether to measure it in the standard or the | The receiver randomly decides for each pulse whether to measure it in the standard or the Hadamard basis, and records the basis and measurement result in a table. | ||
He then reports to the sender the arrival times of all pulses he received, but not the bases or the measurement results. | He then reports to the sender the arrival times of all pulses he received, but not the bases or the measurement results. | ||
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The sender does not know which word she shares with the receiver. | The sender does not know which word she shares with the receiver. | ||
Using the error-correcting code, sender computes the syndromes of the words corresponding to each set, and she sends them to the receiver over an | Using the error-correcting code, sender computes the syndromes of the words corresponding to each set, and she sends them to the receiver over an error free channel. | ||
Given this data, the receiver should be able to recover the original word corresponding to his good set but not that corresponding to his bad set. | Given this data, the receiver should be able to recover the original word corresponding to his good set but not that corresponding to his bad set. | ||
Furthermore, the sender computes the parity of a random subset of each set, and tells the receiver the addresses defining these random subsets, but not the resulting parities. | Furthermore, the sender computes the parity of a random subset of each set, and tells the receiver the addresses defining these random subsets, but not the resulting parities. | ||
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If they are equal, sender gives the xor of same indexed bit and the parity, otherwise she gives him the xor of opposite indexed bit and the parity. | If they are equal, sender gives the xor of same indexed bit and the parity, otherwise she gives him the xor of opposite indexed bit and the parity. | ||
From this, the receiver extracts the desired bit. | From this, the receiver extracts the desired bit. | ||
==Notation== | ==Notation== | ||