System and method for changing the security level of a communications terminal during operation

• US 9,191,200 B1
• Filed: 10/07/2010
• Issued: 11/17/2015
• Est. Priority Date: 10/07/2010
• Status: Active Grant

• Current Assignee: L3 Technologies, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Inventors: Adams, Michael D., Jacobson, Jared M.
• Primary Examiner(s): Schmidt, Kari
• Application Number:
  US12/900,349
• Time in Patent Office: 1,867 Days
• Field of Search: 380/281, 380/284, 380/44, 380/270, 380/277, 380/278, 713/155, 713/189, 726/17
• US Class Current: 1/1
• CPC Class Codes: G06F 21/60 Protecting data
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: G06F 2221/2111 Location-sensitive, e.g. geographical location, GPS
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 2463/062 applying encryption of the keys
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0861 using biometrical features, e.g. fingerprint, retina-scan cryptographic mechanisms or cryptographic arrangements for entity authentication using biological data H04L9/3231
• CPC Class Codes: H04L 63/105 Multiple levels of security
• CPC Class Codes: H04L 63/18 using different networks or channels, e.g. using out of band channels cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/0827; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L9/3215
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/085 Secret sharing or secret splitting, e.g. threshold schemes
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB
• CPC Class Codes: H04W 12/037 of the control plane, e.g. signalling traffic
• CPC Class Codes: H04W 12/041 Key generation or derivation
• CPC Class Codes: H04W 12/0431 Key distribution or pre-distribution; Key agreement
• CPC Class Codes: H04W 12/0471 Key exchange
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

The security level of a communications terminal can be changed during operation. A key loading device can reconstitute a key encryption key from plural split portions. The split portions can be loaded into the key loading device via various interfaces. The reconstituted key encryption key can be used to unwrap wrapped keys stored in the key loading device.

Claims

1. A method of changing the security level of a communications terminal during operation, the method comprising:

providing a key loading device to the communications terminal, wherein the key loading device comprises a secure memory, and stored within the secure memory are;

a wrapped first key (wK1) wrapped utilizing a single key encryption key (KEK) and a first split partial portion (s1KEK) of the single KEK but not a second split partial portion (s2KEK) of the single KEK or a third split partial portion (s3KEK) of the single KEK, wherein the single KEK cannot be reconstituted from less than all of the s1KEK, the s2KEK, and the s3KEK, wherein the s1KEK and the wK1 are at a first security level;

loading the s2KEK into the secure memory of the key loading device via a physical interface to the key loading device;

transferring the s3KEK into the secure memory of the key loading device via a communications link, wherein the communications link is different than the physical interface; and

reconstituting the single KEK from the s1KEK, the s2KEK and the s3KEK, wherein the reconstituted single KEK is at a third security level higher than the first security level;

unwrapping the wK1 using the reconstituted, single KEK to obtain a first key (K1), wherein the K1 is at a second security level higher than the first security level; and

using the K1 within the communications terminal to perform cryptographic operations.

2. The method of claim 1, wherein the communications link is a wireless link provided by the communications terminal.

3. The method of claim 1, wherein the K1 is a key encryption key, the communications link is a first communications link, and further comprising:

receiving a wrapped traffic encryption key (wTEK) over the first communications link;

unwrapping the wTEK using K1 to obtain a traffic encryption key (TEK); and

communicating information encrypted using the TEK over a second communications link provided by the communications terminal.

4. The method of claim 3, further comprising:

receiving a second wrapped traffic encryption key (wTEK2) over the second communications link;

unwrapping the wTEK2 using the K1 to obtain a second traffic encryption key (TEK2); and

communicating information encrypted using the TEK2 over the second communications link.

5. The method of claim 1, wherein the K1 is a traffic encryption key, and further comprising:

communicating information encrypted using the K1 over the communications link.

6. The method of claim 5, further comprising:

receiving a second traffic encryption key (TEK2) over the communications link; and

communicating information encrypted using TEK2 over the communications link.

7. The method of claim 1, wherein the K1 is a key encryption key and further comprising:

unwrapping a second wrapped key (wK2) stored within the key loading device to obtain a second key (K2), wherein the second key is a traffic encryption key;

receiving a wrapped traffic encryption key (wTEK) over the communications link, wherein the communications link is encrypted using K2;

decrypting communications received on the communications link using K2;

unwrapping the wTEK using the K1 to obtain a traffic encryption key (TEK); and

communicating information encrypted using the TEK over the communications link using the communications terminal.

8. The method of claim 7, further comprising:

receiving a wrapped second traffic encryption key (wTEK2) over the communications link, wherein the communications link is encrypted using the K2;

unwrapping the wTEK2 using the K1 to obtain a second traffic encryption key (TEK2); and

communicating information encrypted using the TEK2 over the communications link.

9. The method of claim 1, further comprising:

generating the single KEK;

using the single KEK to wrap the K1;

after using the single KEK to wrap the K1, splitting the single KEK into the s1KEK, s2KEK and s3KEK within the key loading device;

storing the s1KEK in the key loading device;

distributing the s2KEK and the s3KEK outside the key loading device; and

erasing the single KEK, the s2KEK and the s3KEK but not the s1KEK from the key loading device, so that the key loading device is at the first security level.

10. The method of claim 1 further comprising receiving the s2KEK from a first source external to the communications terminal and the key loading device prior to the loading step, and wherein the transferring step comprises receiving via the communications link the s3KEK from a second source different than the first source and external to the communications terminal and the key loading device.

11. The method of claim 1 further comprising, after the step of reconstituting the single KEK:

receiving a second key (K2);

wrapping the K2 using the single reconstituted KEK to form a wrapped second key (wK2); and

storing the wK2 in the secure memory.

12. The method of claim 1, wherein:

during the loading, the physical interface is physically connected directly to the key loading device, and

the transferring comprises transferring the s3KEK into the secure memory of the key loading device from a remotely located storage device via the communications link.

13. A method of preparing a communications terminal for secure operation when the communications terminal security level can be changed during operation, the method comprising:

generating a single key encryption key (KEK) to produce a single generated KEK, wherein the single generated KEK is at a third security level;

wrapping a first key (K1) using the single generated KEK within the secure facility to form a wrapped first key (wK1), wherein the K1 is at a second security level and the wK1 is at the first security level and the first security level is lower than the second security level;

after the wrapping, splitting the single generated KEK into a plurality of at least three split partial portions of the single generated KEK each of which is a split of the single generated KEK within a key loading device, wherein the single generated KEK cannot be reconstituted from less than a predefined number of the plurality of split partial portions of the single generated KEK, wherein the plurality of split partial portions is at the first security level and the first security level is lower than the third security level;

storing the wK1 and at least a first one (s1KEK) of the plurality of split partial portions of the single generated KEK in a secure memory within the key loading device;

providing at least a second one (s2KEK) of the plurality of split partial portions of the single generated KEK to at least one initiation device;

providing at least a third one (s3KEK) of the plurality of split partial portions of the single generated KEK to a communications facility configured to communicate over a communications link with the communications terminal; and

erasing the single generated KEK and all but the at least first one (s1KEK) of the plurality of split partial portions of the single generated KEK from the secure memory, so that the key loading device is at the first security level, wherein after the erasing step, the at least first one (s1KEK) is stored in the secure memory but the at least second one (s2KEK) and the at least third one (s3KEK) are not stored in the secure memory.

14. The method of claim 13, further comprising:

interfacing the initiation device to a physical interface of the key loading device temporarily while at a staging area to allow loading the second split partial portion of the single KEK into the key loading device;

transferring the third split partial portion of the single generated KEK into the key loading device via the communications link;

reconstituting the single generated KEK to form a single reconstituted KEK from the s1KEK, s2KEK, and s3KEK within the key loading device so that the key loading device is at the third security level;

unwrapping the wK1 using the single reconstituted KEK to obtain a first key K1; and

using the first key K1 to perform a cryptographic operation within the communications terminal.

15. The method of claim 14, further comprising:

relocating the communications terminal with the installed key loading device from the staging facility to an operational theatre before transferring the s3KEK into the key loading device; and

erasing the single generated KEK and the communications key before relocating the communications terminal from the operational theatre back to the staging area so that the key loading device is at the first security level.

16. The method of claim 14, wherein the communications link is a wireless link provided by the communications terminal.

17. The method of claim 13, wherein:

the at least one initiation device is a portable crypto ignition key memory, and the step of providing the s2KEK comprises;

temporarily interfacing the crypto ignition key memory to the secure memory,

writing the s2KEK from the secure memory to the crypto ignition key memory, and

removing the crypto ignition key memory from the secure memory;

the communications facility is external to the secure memory, the key loading device, and the communications terminal, and the step of providing the s3KEK comprises transmitting the s3KEK from the secure memory over the communications link to the communications facility.

18. A communications system for changing a security level during operation, the system comprising:

a communications terminal;

an encryption device disposed within the communications terminal and configured to accept a traffic encryption key;

a secure memory coupled to the communications terminal, wherein the secure memory is configured to store a wrapped first key wrapped using a single key encryption key (KEK) and a plurality of split partial portions of the single KEK, wherein a first split partial portion (s1KEK) of the single KEK is stored therein;

a physical interface to the secure memory and configured to temporarily interface physically with a portable crypto ignition key memory and accept from the crypto ignition key memory a second split partial portion (s2KEK) of the single KEK;

a communication interface to the secure memory configured to transfer a third split partial portion (s3KEK) of the single KEK received at the communications terminal from a source external to the communications system into the secure memory; and

a key reconstitutor coupled to the secure memory and configured to reconstitute the single KEK from the s1KEK, s2KEK, and s3KEK; and

a key unwrapper coupled to the secure memory and configured to decrypt the first key using the reconstituted single KEK; and

a key fill interface between the key unwrapper and the encryption device configured to transfer a traffic encryption key into the encryption device, wherein the traffic encryption key is any of;

the first key, a second key unwrapped using the first key, a second key received over an encrypted communications link protected by the first key, and a third key wrapped using a second key and received over an encrypted communications link protected by the first key.

19. The system of claim 18, wherein the communications interface is coupled to the communications terminal to receive the s3KEK via a wireless communications link, which comprises the encrypted communications link or a different communications link.

20. The system of claim 18, wherein the communications terminal comprises a wireless communications link, which comprises the encrypted communications link or a different communications link and is any of:

a satellite communications terminal, a tactical communications terminal, a wireless networking terminal, and a personal communications terminal.

21. The system of claim 18, wherein the communications terminal comprises a wired communications link, which comprises the encrypted communications link or a different communications link and is any of:

an Ethernet link, an optical link, and a dedicated line.

22. The system of claim 18, wherein the encryption device is any of a HAIPE (high assurance internet protocol encryptor) device, an IPsec device, a TRANSEC (transmission security) device, a secure storage device, and a type 1 cryptographic unit.

23. A key loading device for changing the security level of a communications terminal, the key loading device comprising:

a secure memory configured to store a first split partial portion (s1KEK) of a single key encryption key (KEK), and a wrapped (wK1) first key (K1) wrapped by the single KEK;

a data input port coupled to the secure memory and configured to temporarily interface physically with a portable crypto ignition key memory and accepting from the crypto ignition key memory a second split partial portion (s2KEK) of the single KEK and storing the s2KEK into the secure memory;

a terminal interface configured to interface to a communications terminal that is remotely located from the key loading device, accept a third split partial portion (s3KEK) of the single KEK from the remote communications terminal, and store the s3KEK into the secure memory;

a means for combining the s1KEK, s2KEK and s3KEK to reconstitute the single KEK, the means for combining being coupled to the secure memory, wherein the s1KEK, s2KEK and s3KEK are at a first security level, the single KEK cannot be reconstituted from less than all of the s1KEK, s2KEK and s3KEK, and the single KEK is at a third security level higher than the first security level;

a means for unwrapping the wK1 using the reconstituted single KEK to obtain the K1, the means for unwrapping being coupled to the secure memory; and

a key output port configured to transfer a traffic key to cryptographic unit of the communications terminal.

24. The device of claim 23, wherein the K1 is the traffic key.

25. The device of claim 23, wherein a wrapped (wK2) second key (K2) is stored in the secure memory, and further comprising a means for unwrapping the wK2 using the K1 to obtain the second key K2, and the K2 is the traffic key.

26. The device of claim 23, wherein a wrapped (wK2) second key (K2) is received from the communications terminal, and further comprising a means for unwrapping the wK2 using the single reconstituted KEK to obtain the second key K2, and the K2 is the traffic key.

27. The device of claim 23, wherein the key output port is any of:

a DS-101 interface, a DS-102 interface, a universal serial bus interface, an RS-232 interface, an RS-422 interface, an Ethernet interface, a firewire interface, an SD (secure digital) interface, an SDIO (secure digital input output) interface, an eSATA (external serial advanced technology attachment) interface, and a USB (universal serial bus).