Method and apparatus for ad hoc cryptographic key transfer

• US 7,620,187 B1
• Filed: 03/30/2005
• Issued: 11/17/2009
• Est. Priority Date: 03/30/2005
• Status: Expired due to Fees

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Cross, Ray Lynn, Didier, Patrick Francis, Ossenkop, Stephen Edward, Odell, Roger Charles
• Primary Examiner(s): Dada; Beemnet W
• Application Number:
  US11/096,700
• Time in Patent Office: 1,693 Days
• Field of Search: 380/277, 380/278, 380/279, 380/281, 380/282, 380/286, 380/247, 713/175, 713/173
• US Class Current: 380/279
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]

Abstract

Method and apparatus for obtaining a cryptographic key by dispatching a key request to a communications channel, receiving a response from one or more key sources, selecting a key source according to the received responses, preparing a requester credential, communicating the requester credential to the selected key source, receiving a source credential from the selected key source, receiving an encrypted key from the key source and decrypting the encrypted key source according to the received source credential, the requester credential and a pre-placed certificate.

Claims

1. A method for obtaining a cryptographic key comprising:

dispatching a key request to a communications channel;

receiving a response from one or more key sources from the communications channel;

selecting a key source according to one or more responses from one or more key sources;

preparing a requester credential;

communicating the requester credential to the selected key source;

receiving a source credential from the selected key source;

receiving an encrypted first cryptographic-key from the selected key source; and

decrypting the received encrypted first cryptographic-key according to the received source credential, the requester credential and a pre-placed certificate.

2. The method of claim 1 wherein dispatching a key request to a communications channel comprises:

generating a modulated carrier according to a key request; and

modifying at least one of a frequency, a phase, an amplitude, a start time, jitter, encoding code, modulation code, modulation type, polarization modulation, pulse rise time, pulse fall time, bit ordering and interleaving exhibited by the modulated carrier according to a secure algorithm.

3. The method of claim 1 wherein dispatching a key request to a communications channel comprises:

encrypting the key request according to a communications channel encryption key;

generating a modulated carrier according to the encrypted key request; and

modifying at least one of a frequency, a phase, an amplitude, a start time, jitter, encoding code, modulation code, modulation type, polarization modulation, pulse rise time, pulse fall time, bit ordering and interleaving exhibited by the modulated carrier according to a secure algorithm.

4. The method of claim 1 further comprising validating the received source credential according to a time stamp included therein.

5. The method of claim 1 further comprising:

generating a representation code for the received first cryptographic key;

authenticating the representation code according to a requester identifier; and

dispatching the authenticated representation code to the key source.

6. The method of claim 1 further comprising:

determining the authenticity of the cryptographic-key as an original source key when a cryptographic-key is still encrypted with a key encryption key; and

decrypting the cryptographic key according to a key encryption key when the encrypted cryptographic-key is authentic.

7. The method of claim 1 further comprising:

receiving a second cryptographic key in a message that is encrypted according to the decrypted received cryptographic key.

8. A method for providing a cryptographic key comprising:

receiving a key request on a communications channel;

determining if the key request can be satisfied;

responding to the key request with a source identifier when the key-request can be satisfied;

receiving a requester credential from a remote terminal;

determining when the requester credential is valid;

establishing a communications channel with the remote terminal when the requester credential is valid; and

encrypting a cryptographic key according to the requester credential, the source credential and a counterpart to a certificate that is pre-placed in the requester; and

conveying the encrypted cryptographic-key to the remote terminal using the communications channel.

9. The method of claim 8 wherein determining when the received key request can be satisfied comprises at least one of determining that they key requester is included in a permission list and determining that the key requester is not included in a rejection list.

10. The method of claim 8 wherein determining when the requester credential is valid comprises at least one of determining that the requester credential is included in a permission list and determining that the requester credential is not included in a rejection list.

11. A secure terminal comprising:

a pre-placed certificate register storing a pre-placed certificate received from a data transfer device;

a communications unit wirelessly communicating with a remotely located key source;

a source identification unit dispatching a key request by means of the communications unit, receiving a source identification message from the communications unit and further selecting a key source according to a received source identification message;

a key request unit incorporating a local credential into a key request, dispatching by means of the communications unit the key request to a key source selected by the source identification unit and receiving an encrypted key from the key source by means of the communications unit; and

a decryption unit receiving from the key source by means of the communications unit a source credential and further decrypting an encrypted key according to the source credential, the local credential and a pre-placed certificate stored in the pre-placed certificate register.

12. The secure terminal of claim 11 wherein the communication unit comprises:

a modulator generating a carrier according to data received from at least one of the source identification unit and the key request unit;

a demodulator extracting data from a carrier and providing the data to at least one of the source identification unit, the key request unit and the decryption unit; and

a secure waveform modulator modifying a carrier generated by the modulator and modifying the extraction provided by the demodulator according to a secure data algorithm by varying a frequency, a phase, an amplitude, a start time, jitter, encoding code, modulation code, modulation type, polarization modulation, pulse rise time, pulse fall time, bit ordering and interleaving.

13. The secure terminal of claim 11 wherein the communication unit comprises:

a message encryption unit encrypting data received from at least one of the source identification unit and the key request unit;

a modulator generating a carrier according to data encrypted by the encryption unit;

a demodulator extracting data from a carrier;

a message decryption unit decrypting data receive from the demodulator and providing decrypted data to at least one of the source identification unit, the key request unit and the decryption unit; and

a secure waveform modulator modifying a carrier generated by the modulator and modifying the extraction provided by the demodulator according to a secure data algorithm by varying a frequency, a phase, an amplitude, a start time, jitter, encoding code, modulation code, modulation type, polarization modulation, pulse rise time, pulse fall time, bit ordering and interleaving.

14. A secure terminal comprising:

a processor executing an instruction sequence;

a modulator generating a carrier according to data received from the processor;

a demodulator providing data to the processor by demodulating a received carrier;

a memory storing one or more instruction sequences and information;

one or more instruction sequences stored in the memory including;

a source identification module that, when executed by the processor, minimally causes the processor to;

convey a key request to the modulator;

receive from the demodulator one or more key source identification messages; and

select a key source according to a received key source identification message;

a key request module that, when executed by the processor, minimally causes the processor to;

convey to the modulator a requester credential message that includes a requester credential; and

receive from the demodulator a source credential and an encrypted cryptographic key; and

a decryption module that, when executed by the processor, minimally causes the processor to decrypt the received cryptographic key according to the received source credential, the requester credential and a pre-placed certificate that is included in the memory.

15. The secure terminal of claim 14 further comprising a secure waveform modulator causing modification, according to a secure algorithm, a carrier generated by the modulator and a demodulation process performed by the demodulator.

16. The secure terminal of claim 14 further comprising:

a secure waveform modulator modifying according to a secure algorithm a carrier generated by the modulator and demodulation performed by the demodulator; and

a channel security module stored in the memory that, when executed by the processor, minimally causes the processor to encrypt information conveyed to the modulator according to an encryption key stored in the memory and decrypt information received from the demodulator according to an encryption key stored in the memory.

17. The secure terminal of claim 14 further comprising a representation code module stored in the memory that, when executed by the processor, minimally causes the processor to:

generate a representation code according to a received decrypted cryptographic key; and

convey the representation code to the modulator.

18. The secure terminal of claim 14 further comprising a key encryption key module stored in the memory that, when executed by the processor, minimally causes the processor to further decrypt according to a key encryption key a cryptographic key stored in the memory when the cryptographic key is authenticated to an original key source and when said cryptographic key is still encrypted according to a key encryption key.

19. The secure terminal of claim 14 further comprising a time validation module that, when executed by the processor, minimally causes the processor to validate any portion or all of a key request transaction according to a time stamp included therein.

20. A key source apparatus comprising:

a wireless communications unit communicating with a remotely located key requester;

a requester validation unit generating a valid requester signal when a key request received by the communications unit is valid;

a source identification unit directing a source identification message to a key requester by means of the communications unit in response to the valid requester signal;

a request validation unit generating a valid request signal when a requester credential message is received by the communications unit from a key requester;

a key cache storing one or more cryptographic keys;

a key encryption unit encrypting a cryptographic key stored in the key cache, wherein said encryption is accomplished according to a source credential, a received requester credential and a counterpart to a certificate that has been pre-placed in the key requester and wherein the key encryption unit directs an encrypted cryptographic key to a key requester by means of the communications unit.

21. The key source of claim 20 further comprising a permission list and a rejection list and wherein the permission list and the rejection list are used by the requester validation unit as an input to a comparison used to generate the valid requester signal and are further used by the request validation unit as an input to a comparison used to generate a valid request signal.