Large scale quantum cryptographic key distribution network

1. A method, comprising:

obtaining, at a first satellite, first encryption key symbols, by at least one of generating the first encryption key symbols at the first satellite in response to key distribution instructions or retrieving the first encryption key symbols stored at the first satellite in response to the key distribution instructions;

receiving, at a first land-based node, the first encryption key symbols transmitted from the first satellite across a first free-space link using first quantum cryptographic techniques;

receiving, at a second land-based node, second encryption key symbols transmitted from a second satellite across a second free-space link using second quantum cryptographic techniques;

distributing the first encryption key symbols from the first land-based node towards a first customer site using third quantum cryptographic techniques; and

distributing the second encryption key symbols from the second land-based node towards a second customer site using fourth quantum cryptographic techniques, where the first and second encryption key symbols are used for encrypting traffic sent between the first and second customer sites.

2. The method of claim 1 , where the first encryption key symbols and the second encryption key symbols are the same encryption key symbols.

3. The method of claim 1 , where the first and second satellites are the same satellite.

4. The method of claim 1 , where the first and second satellites are space-based satellites.

5. The method of claim 1 , where the first and second quantum cryptographic techniques are the same quantum cryptographic technique.

6. A system, comprising:

means for obtaining, at a first satellite, first encryption key symbols, by at least one of generating the first encryption key symbols at the first satellite in response to key distribution instructions or retrieving the first encryption key symbols stored at the first satellite in response to the key distribution instructions;

means for receiving, at a first land-based node, the first encryption key symbols transmitted from the first satellite across a first free-space link using first quantum cryptographic techniques;

means for receiving, at a second land-based node, second encryption key symbols transmitted from a second satellite across a second free-space link using second quantum cryptographic techniques;

means for distributing the first encryption key symbols from the first land-based node towards a first customer site using third quantum cryptographic techniques; and

means for distributing the second encryption key symbols from the second land-based node towards a second customer site using fourth quantum cryptographic techniques, where the first and second encryption key symbols are used for encrypting traffic sent between the first and second customer sites.

7. The system of claim 6 , where the first encryption key symbols and the second encryption key symbols are the same encryption key symbols.

8. The system of claim 6 , where the first and second satellites are the same satellite.

9. The system of claim 6 , where the first and second satellites are space-based satellites.

10. The system of claim 6 , where the first and second quantum cryptographic techniques are the same quantum cryptographic technique.

11. A system, comprising:

a first satellite to:

receive key distribution instructions, and

obtain, in response to the key distribution instructions, first encryption key symbols, where, when obtaining the first encryption key symbols, the first satellite at least one of:

generates the first encryption key symbols at the first satellite in response to key distribution instructions, or

retrieves the first encryption key symbols stored at the first satellite;

a first land-based node to:

receive the first encryption key symbols transmitted from the first satellite across a first free-space link using first quantum cryptographic techniques, and

distribute the first encryption key symbols from the first land-based node towards a first customer site using third quantum cryptographic techniques; and

a second land-based node to:

receive second encryption key symbols transmitted from a second satellite across a second free-space link using second quantum cryptographic techniques, and

distribute the second encryption key symbols from the second land-based node towards a second customer site using fourth quantum cryptographic techniques, where the first and second encryption key symbols are used for encrypting traffic sent between the first and second customer sites.

12. The system of claim 11 , where the first encryption key symbols and the second encryption key symbols are the same encryption key symbols.

13. The system of claim 11 , where the first and second satellites are the same satellite.

14. The system of claim 11 , where the first and second satellites are space-based satellites.

15. The system of claim 11 , where the first and second quantum cryptographic techniques are the same quantum cryptographic technique.