Pedigrees for quantum cryptography

• US 20070192598A1
• Filed: 01/09/2006
• Published: 08/16/2007
• Est. Priority Date: 01/09/2006
• Status: Active Grant

• Current Assignee: Raytheon BBN Technologies Corp. (Rtx Corporation)
• Original Assignee: Raytheon BBN Technologies Corp. (Rtx Corporation)
• Inventors: Elliott, Brig, Pearson, David, Troxel, Gregory
• Granted Patent: US 8,082,443 B2
• Time in Patent Office: Days
• US Class Current: 713/168
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 9/0852 Quantum cryptography transmission systems employing electromagnetic waves other than radio waves, e.g. light, infrared H04B10/00; wavelength-division multiplex systems H04J14/02; WDM arrangements H04J14/03
• CPC Class Codes: H04L 9/0858 Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding

Abstract

A system stores pedigrees that include details of how and when each of multiple blocks of encryption key material were distributed between two endpoints using quantum cryptographic techniques. The system receives an indication of a possible quantum cryptographic security violation and accesses the stored pedigrees to identify one or more of the multiple blocks of encryption key material that may have been compromised.

Claims

1. A method, comprising:

communicating a sequence of symbols using quantum cryptographic mechanisms between two nodes to derive a block of encryption key material; and

constructing a pedigree that includes details of how and when the block of encryption key material was produced using the quantum cryptographic mechanisms.

2. The method of claim 1, wherein the pedigree further includes information related to classical cryptography.

3. The method of claim 1, further comprising:

using the stored pedigree when investigating possible quantum cryptographic key distribution security violations.

4. The method of claim 1, further comprising:

publicly discussing the communicated sequence of symbols between the two nodes to derive the block of encryption key material from the sequence of symbols.

5. The method of claim 1, further comprising:

storing the constructed pedigree in a database.

6. The method of claim 1, further comprising:

using the block of encryption key material for encrypting traffic sent between the two nodes via a public channel.

7. The method of claim 6, wherein the database is remotely located and wherein storing the constructed pedigree in a database comprises:

transmitting the pedigree across a network to store the pedigree in the database.

8. The method of claim 1, further comprising:

appending a digital signature to the constructed pedigree to certify its authenticity.

9. The method of claim 1, wherein the details of how and when the block of encryption key material was produced include at least one of the following:

a) whether an underlying optical system used for symbol communication using quantum cryptographic mechanisms is based on an attenuated laser pulse, a true single photon source, or pairs of entangled photons;

b) a mean photon number if an underlying optical system used for symbol communication using quantum cryptographic mechanisms comprises an attenuated laser;

c) error bounds that an error detection and correction protocol associated with the symbol communication using quantum cryptographic mechanisms is designed to achieve;

d) an amount of privacy amplification used for deriving the block of encryption key material;

e) an identification of the two nodes that participated in the symbol communication using quantum cryptographic mechanisms;

f) a unique identifier for the sequence of symbols communicated using quantum cryptographic mechanisms;

g) times at which the block of encryption key material was derived, including the starting and ending times for communicating the sequence of symbols using quantum cryptographic mechanisms;

h) an observed error rate associated with the communication of the sequence of symbols;

i) an estimated entropy rate for the derived block of encryption key material;

j) times at which QKD protocols that derived the block of encryption key material operated;

k) an identification of one or more of QKD protocols used to derive the block of encryption key material;

l) a size of the block of encryption key material;

m) parameters of a security guarantee associated with the block of encryption key material;

or

n) a random number(s) used in deriving the block of encryption key material.

10. A system, comprising:

a quantum cryptographic transmitter configured to transmit a sequence of symbols using quantum cryptographic mechanisms to a node;

a network interface configured to publicly discuss the transmitted sequence of symbols with the node to derive the block of encryption key material from the sequence of symbols; and

a processing unit configured to construct a pedigree that includes details of how and when the block of encryption key material was produced using the quantum cryptographic mechanisms.

11. A method, comprising:

communicating symbols using quantum cryptographic mechanisms between a first endpoint and a second endpoint;

publicly discussing the symbols between the first endpoint and the second endpoint to obtain a block of encryption key material;

noting parameters associated with the quantum cryptographic symbol transmission and/or the public discussion; and

storing the noted parameters as a pedigree for the block of encryption key material.

12. The method of claim 11, wherein the noted parameters further include information related to classical cryptography.

13. The method of claim 11, further comprising:

using the pedigree when investigating possible quantum cryptographic key distribution security violations.

14. The method of claim 11, wherein the noted parameters indicate how and when the block of encryption key material was produced using the quantum cryptographic mechanisms.

15. The method of claim 11, wherein the noted parameters comprise at least one of the following:

a) whether an underlying optical system used for symbol communication using quantum cryptographic mechanisms is based on an attenuated laser pulse, a true single photon source, or pairs of entangled photons;

b) a mean photon number if an underlying optical system used for symbol communication using quantum cryptographic mechanisms comprises an attenuated laser;

c) error bounds that an error detection and correction protocol associated with the symbol communication using quantum cryptographic mechanisms is designed to achieve;

d) an amount of privacy amplification used for obtaining the block of encryption key material;

e) an identification of the first endpoint and/or second endpoint that participated in the symbol communication using quantum cryptographic mechanisms;

f) a unique identifier for the symbols communicated using quantum cryptographic mechanisms;

g) times at which the block of encryption key material was obtained, including the starting and ending times for communicating the symbols using quantum cryptographic mechanisms;

h) an observed error rate associated with the communication of the symbols;

i) an estimated entropy rate for the obtained block of encryption key material;

j) times at which QKD protocols that were used to obtain the block of encryption key material operated;

k) an identification of one or more QKD protocols used to obtain the block of encryption key material;

or

l) information related to authentication used in publicly discussing the communicated symbols.

16. A system, comprising:

a quantum cryptographic receiver configured to receive symbols transmitted from a node using quantum cryptographic mechanisms;

a network interface configured to publicly discuss the received symbols with the node to obtain a block of encryption key material; and

a processing unit configured to;

identify parameters associated with the symbol transmission and/or the public discussion, and

store the identified parameters as a pedigree for the block of encryption key material.

17. A method, comprising:

storing pedigrees that include details of how and when each of a plurality of blocks of encryption key material were distributed between two endpoints using quantum cryptographic techniques;

receiving an indication of a possible quantum cryptographic security violation; and

accessing the stored pedigrees to identify one or more of the plurality of blocks of encryption key material that may have been compromised.

18. The method of claim 17, further comprising:

accessing the stored pedigrees to determine how and when the identified one or more of the plurality of blocks of encryption key material were distributed.

19. The method of 17, wherein accessing the stored pedigrees to identify one or more encryption keys that may have been compromised further comprises:

using the stored pedigrees to identify encryption material that may have been compromised by an eavesdropper.

20. A method, comprising:

storing pedigrees that include details of how and when each of a plurality of blocks of encryption key material were produced using quantum cryptographic techniques; and

using the stored pedigrees to ascertain the extent and/or nature of a possible security violation.

21. A system, comprising:

a database configured to store pedigrees that include details of how and when each of a plurality of blocks of encryption key material were produced using quantum cryptographic techniques;

a processing unit configured to;

receive an indication of a possible quantum cryptographic security violation, and

access the stored pedigrees to identify one or more encryption keys that may have been compromised.

22. A computer-readable medium that stores computer-executable instructions, comprising:

instructions for transmitting symbols using quantum cryptographic mechanisms via a quantum channel to a node;

instructions for discussing the transmitted symbols with the node via a public channel to derive a block of encryption key material; and

instructions for constructing a pedigree that includes details of how and when the block of encryption key material was produced using quantum cryptographic techniques.

23. A system, comprising:

means for storing pedigrees that include details of how and when each of a plurality of blocks of encryption key material were produced using quantum cryptographic techniques; and

means for using the stored pedigrees to ascertain the extent or nature of a possible security violation.