Maryland's Defense Patent Database

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Quantum key distribution protocol process

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A communication process is provided for sending a qubit message between Alice and Bob using a quantum channel for obviating a faked-state attack by Eve. The qubit message is composed of ensemble bits and transmitted as a plurality of photons into the quantum channel. Each photon has a corresponding bit value. The process includes: Alice preparing three uniformly random bit strings each of length 4N to produce strings R (raw key), P (bit basis) and U (unitary operation), and Bob preparing two uniformly random bit strings of the same length to produce strings M (bit basis) and V (unitary operation). Alice broadcasts P, applies her unitary operation and records a first weak measurement to the photons for transmission. Meanwhile Bob broadcasts M, applies his unitary operation and records both a second weak measurement and a strong measurement to the photons. Alice segregates her key and weak measurement strings to produce corresponding truncated strings from differing bases in P and M, and broadcasts the truncated key string. Bob segregates his weak and strong measurement strings from the differing bases to produce corresponding truncated strings, broadcasting the truncated strong measurement string. Bob then compares an average of his truncated weak measurement string to a security threshold as a first condition. Alice compares an average of her truncated weak measurement string to the security threshold as a second condition. If both conditions are satisfactory, Alice segregates a new truncated key string from R by selecting same bases in P and M for sending to Bob.

Troupe, James E.
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503 days
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