Appeal 2007-2437
Application 09/816,080
Appellant argues that Mayers discloses a method for testing the
security of a quantum cryptographic system used for quantum key
distribution. Appellant argues that Mayers method utilizes polarization
states of photons with the photons possessing quantum states satisfying
certain relationships between three bases (Br. 6). Appellant argues that the
presently claimed invention concerns a key arrangement method including a
first system that encodes a bit sequence and sends it to a second system (Br.
7). The second system decodes the received signals and measures the signal
values. In contrast to the Mayers’s system, in the presently claimed
invention, the second system records some second values, which are above a
predetermined value, and tells the first system the bit positions of the
selected bits (Br. 7). The first system selects values corresponding to those
bit positions, and discards the rest of the values (Br. 7). Appellant argues
that in comparing the present invention to Mayers, it is clear that Mayers
does not adopt only bits having a measured value beyond a threshold value
(Br. 7). Appellant argues that as disclosed in Mayers, if a sufficient number
of bits meet a parity test, it is concluded that there is no eavesdropping
activity. The bits that have been tested or discarded in a shared key is
produced from the remaining random series of bits (Br. 7). Appellant
argues that in contrast, and as recited in claim 1, the second system adopts
only those bits having a measured value beyond the threshold value, and
informs the first system of the bit positions of the selected bits. The adopted
bits are then used as a key string for the first and second systems (Br. 7).
Appellant argues that Mayers discloses instead to discard the bits that are
actually tested, and utilize the remaining random series of bits to form a
shared key (Br. 7-8), and that in the present invention, it is the second
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