Multi-user quantum key distribution apparatus

1 . A quantum key distribution apparatus, comprising:

a light source that generates and outputs an optical pulse having a single photon,

wherein the quantum key distribution apparatus is configured such that:

the optical pulse in which information for private key generation is included is transmitted to multiple receivers, respectively, through different communication paths, and

the light source generates the optical pulse at a speed higher than an optical pulse measurement speed of each of the multiple receivers by a multiple of a number of multiple receivers.

2 . The quantum key distribution apparatus of claim 1 , further comprising:

an encoder that encodes private key information into the optical pulse generated by the light source;

an optical splitter that divides and outputs optical pulses in which the private key information is encoded into communication paths corresponding to the number of multiple receivers; and

multiple switches that turns on/off the communication paths connected to the multiple receivers, respectively.

3 . The quantum key distribution apparatus of claim 2 , wherein the encoder encodes different pieces of private key information into respective optical pulses.

4 . The quantum key distribution apparatus of claim 2 , wherein the multiple switches are turned on at intervals of periods corresponding to optical pulse measurement speeds of the multiple receivers.

5 . A quantum key distribution apparatus, comprising:

a light source that generates and outputs an optical pulse having a single photon, wherein the optical pulse includes information for private key generation; and

a wavelength division multiplexing unit that separates the optical pulse into optical pulses for respective wavelengths and simultaneously transmits the optical pulses for respective wavelengths to multiple receivers through a single communication path,

wherein the light source generates the optical pulse at a speed higher than an optical pulse measurement speed of each of the multiple receivers.

6 . The quantum key distribution apparatus of claim 5 , further comprising:

an encoder that encodes private key information into the optical pulse generated by the light source.

7 . The quantum key distribution apparatus of claim 6 , wherein the encoder encodes different pieces of private key information for respective wavelengths of the optical pulse.

8 . A quantum key distribution apparatus, comprising:

a light source that generates and outputs an optical pulse having a single photon, wherein the optical pulse includes information for private key generation;

an optical splitter that divides the optical pulse into M communication paths, M being a positive integer greater than 1; and

M wavelength division multiplexing units that separate the optical pulse in each communication path into optical pulses for N respective wavelengths and simultaneously transmit the optical pulses for respective wavelengths to N receivers, N being a positive integer greater than 1,

wherein the light source generates the optical pulse at a speed that is M times higher than an optical pulse measurement speed of each of the multiple receivers.

9 . The quantum key distribution apparatus of claim 8 , further comprising:

an encoder that encodes private key information in the optical pulse generated by the light source; and

M switches configured to that selectively turn on/off the M communication paths,

wherein each of the M switches is connected between the optical splitter and a corresponding one of the M wavelength division multiplexing units.

10 . The quantum key distribution apparatus of claim 9 , wherein the encoder encodes different pieces of private key information for respective wavelengths of the optical pulse.

11 . The quantum key distribution apparatus of claim 8 , wherein each of the switches is turned on at intervals of a period corresponding to an optical pulse measurement speed of each of the multiple receivers.