Method and system for decoupling user authentication and data encryption on mobile devices

• US 9,137,659 B2
• Filed: 07/16/2013
• Issued: 09/15/2015
• Est. Priority Date: 04/25/2013
• Status: Active Grant

• Current Assignee: FusionPipe Software Solutions Inc.
• Original Assignee: FusionPipe Software Solutions Inc.
• Inventors: Khosravi, Hassan, Muslukhov, Ildar, Luong, Peter
• Primary Examiner(s): HOFFMAN, BRANDON S
• Application Number:
  US13/943,070
• Publication Number:
  US 20140321641A1
• Time in Patent Office: 791 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 2463/062 applying encryption of the keys cryptographic mechanisms or cryptographic arrangements for key distribution using key encryption key H04L9/0822
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/0844 with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/50 Secure pairing of devices

Abstract

A method for decoupling user authentication and data encryption on mobile devices includes generating an encryption key (“EK”) for encrypting data and a key encryption key (“KEK”) for encrypting the EK, obtaining an encrypted EK by encrypting the EK using the KEK, storing the encrypted EK on a data container device (“DCD”), and storing the KEK on a key vault device (“KVD”) that is distinct from the DCD. Neither the EK nor KEK are generated using a user authentication secret as a seed. The DCD may fetch the KEK from the KVD as desired to decrypt the EK and to encrypt and decrypt data stored on the DCD. Examples of the DCD include a memory stick, smartphone, or tablet computer, while examples of the KVD include a dongle, smartphone, or tablet computer.

Claims

1. A method for decoupling user authentication and data encryption on mobile devices, the method comprising:

(a) generating an encryption key (“

EK”

) for encrypting data and a key encryption key (“

KEK”

) for encrypting the EK, wherein neither the EK nor the KEK are generated using a user authentication secret as a seed;

(b) obtaining an encrypted EK by encrypting the EK using the KEK;

(c) storing the encrypted EK on a data container device (“

DCD”

);

(d) storing the KEK on a key vault device (“

KVD”

) that is distinct from the DCD;

(e) generating a KEK identifier (“

KEK_ID”

) that identifies the KEK; and

(f) storing the KEK ID in memory accessible to an application resident on the DCD that accesses the data and on the KVD.

2. The method of claim 1 wherein the DCD generates the KEK, the EK, and the KEK_ID, and further comprising deleting the KEK from the DCD following encrypting the EK.

3. The method of claim 1 wherein the application encrypts or decrypts the data by:

(a) obtaining the EK;

(b) encrypting or decrypting the data using the EK; and

(c) deleting the EK following encryption or decryption.

4. The method of claim 3 wherein obtaining the EK comprises:

(a) sending a request from the application for the EK, wherein the request comprises the KEK_ID;

(b) retrieving, from the KVD, the KEK that the KEK_ID identifies;

(c) decrypting, on the DCD, the EK encrypted using the KEK retrieved from the KVD; and

(d) sending the EK decrypted using the KEK to the application.

5. The method of claim 3 wherein obtaining the EK comprises:

(a) sending a request from the application for the EK, wherein the request comprises the KEK_ID;

(b) determining whether the EK is cached on the DCD; and

(c) when the EK is cached on the DCD, sending the EK that is cached on the DCD to the application.

6. The method of claim 1 further comprising safeguarding the data by deleting one or both of the EK and KEK.

7. The method of claim 1 wherein the DCD comprises a memory stick.

8. The method of claim 1 wherein the EK and KEK expire and further comprising replacing the EK and KEK that expire with a different EK and a different KEK, respectively.

9. The method of claim 1 wherein the KVD and DCD are wirelessly linked.

10. The method of claim 9 wherein the Bluetooth™

Low Energy protocol is used to link the KVD and DCD.

11. The method of claim 9 further comprising:

(a) determining whether the KVD and DCD cease to be wirelessly linked; and

(b) deleting the EK from the DCD when the KVD and DCD cease to be wirelessly linked.

12. The method of claim 9 further comprising wirelessly pairing the KVD and DCD by:

(a) generating a weak shared secret key (“

WS2K”

) on the KVD and DCD;

(b) mutually authenticating the KVD and DCD to each other using the WS2K;

(c) following mutual authentication, generating a strong secure session key (“

S3K”

) on the KVD and DCD; and

(d) encrypting subsequent communications between the KVD and DCD using the S3K.

13. The method of claim 12 wherein the S3K expires and further comprising replacing the S3K that expires with a different S3K.

14. The method of claim 12 wherein an Out of Bounds or Passkey Entry Bluetooth™

Low Energy association model is used to generate the WS2K.

15. The method of claim 1 wherein a key vault system manager (“

KVSM”

) is wirelessly communicative with at least one of the KVD and DCD, and further comprising;

(a) sending device health information from each of the at least one of the KVD and DCD to the KVSM;

(b) determining a health status of each of the at least one of the KVD and DCD based on the device health information; and

(c) deleting the EK and KEK based on the health status.

16. The method of claim 15 wherein each of the at least one of the KVD and DCD determines its own health status.

17. The method of claim 15 wherein the KVSM determines the health status of each of the at least one of the KVD and DCD and pushes the health status to each of the at least one of the KVD and DCD.

18. The method of claim 15 further comprising backing up the EK, KEK, and KEK_ID by pushing them from the DCD and KVD to the KVSM.

19. The method of claim 1 wherein the EK is encrypted using a public key having a linked private key, and further comprising recovering encrypted data following loss of one or both of the encrypted EK and KEK by:

(a) decrypting, using the private key, the EK encrypted using the public key;

(b) generating a new KEK, wherein the new KEK is not generated based on the user authentication secret;

(c) generating a new encrypted EK by encrypting the EK using the new KEK;

(d) storing the new encrypted EK on the DCD; and

(e) storing the new encrypted KEK on the KVD.

20. The method of claim 1 wherein the EK and KEK are generated pseudorandomly.

21. A method for decoupling user authentication and data encryption on mobile devices, the method comprising:

(a) decrypting an encrypted encryption key (“

EK”

) stored on a data container device (“

DCD”

) by;

(i) wirelessly retrieving to the DCD from a key vault device (“

KVD”

) a key encryption key (“

KEK”

) used to encrypt the EK; and

(ii) decrypting the encrypted EK using the KEK; and

(b) encrypting or decrypting data stored on the DCD using the EK, wherein neither the EK nor the KEK are generated using a user authentication secret as a seed;

(c) generating a KEK identifier (“

KEK_ID”

) that identifies the KEK; and

(d) storing the KEK_ID in memory accessible to an application resident on the DCD that accesses the data and on the KVD.

22. The method of claim 21 further comprising deleting the EK from the DCD following encrypting or decrypting data.

23. The method of claim 21 further comprising, prior to decrypting the encrypted EK:

(a) generating the EK and the KEK;

(b) obtaining the encrypted EK by encrypting the EK using the KEK;

(c) storing the encrypted EK on the DCD; and

(d) storing the KEK on the KVD.

24. The method of claim 23 wherein the DCD generates the KEK, the EK, and the KEK_ID, and further comprising deleting the KEK from the DCD following encrypting EK.

25. The method of claim 23 wherein wirelessly retrieving the KEK from the KVD comprises:

(a) sending a request for the KEK_ID from the DCD to the KVD, wherein the request comprises the KEK_ID; and

(b) sending the KEK that the KEK_ID identifies from the KVD to the DCD.

26. The method of claim 21 further comprising safeguarding the data by deleting one or both of the EK and KEK.

27. The method of claim 21 wherein the DCD comprises a memory stick.

28. The method of claim 21 wherein the EK and KEK expire and further comprising replacing the EK and KEK that expire with a different EK and a different KEK, respectively.

29. The method of claim 21 wherein Bluetooth™

Low Energy protocol is used to link the KVD and DCD.

30. The method of claim 21 further comprising:

(a) determining whether the KVD and DCD cease to be wirelessly linked; and

(b) deleting the EK from the DCD when the KVD and DCD cease to be wirelessly linked.

31. The method of claim 21 further comprising wirelessly pairing the KVD and DCD by:

(a) generating a weak shared secret key (“

WS2K”

) on the KVD and DCD;

(b) mutually authenticating the KVD and DCD to each other using the WS2K;

(c) following mutual authentication, generating a strong secure session key (“

S3K”

) on the KVD and DCD; and

(d) encrypting subsequent communications between the KVD and DCD using the S3K.

32. The method of claim 31 wherein the S3K expires and further comprising replacing the S3K that expires with a different S3K.

33. The method of claim 31 wherein an Out of Bounds or Passkey Entry Bluetooth™

Low Energy association model is used to generate the WS2K.

34. The method of claim 21 wherein a key vault system manager (“

KVSM”

) is wirelessly communicative with at least one of the KVD and DCD, and further comprising;

(a) sending device health information from each of the at least one of the KVD and DCD to the KVSM;

(b) determining a health status of each of the at least one of the KVD and DCD based on the device health information; and

(c) deleting the EK and KEK based on the health status.

35. The method of claim 34 wherein each of the at least one of the KVD and DCD determines its own health status.

36. The method of claim 34 wherein KVSM determines the health status of each of the at least one of the KVD and DCD and pushes the health status to each of the at least one of the KVD and DCD.

37. The method of claim 34 further comprising backing up the EK, KEK, and KEK_ID by pushing them from the DCD and KVD to the KVSM.

38. The method of claim 21 wherein the EK is encrypted using a public key having a linked private key, and further comprising recovering encrypted data following loss of one or both of the encrypted EK and KEK by:

(a) decrypting, using the private key, the EK encrypted using the public key;

(b) generating a new KEK, wherein the new KEK is not generated based on the user authentication secret;

(c) generating a new encrypted EK by encrypting the EK using the new KEK;

(d) storing the new encrypted EK on the DCD; and

(e) storing the new encrypted KEK on the KVD.

39. The method of claim 21 wherein the EK and KEK are generated pseudorandomly.

40. A system for decoupling user authentication and data encryption on mobile devices, the system comprising:

(a) a data container device (“

DCD”

) wirelessly linked to a key vault device (“

KVD”

), the DCD comprising a DCD memory and a DCD controller communicative with the DCD memory, the DCD memory having encoded thereon statements and instructions cause the DCD controller to;

(i) generate an encryption key (“

EK”

) for encrypting data and a key encryption key (“

KEK”

) for encrypting the EK, wherein neither the EK nor the KEK are generated using a user authentication secret as a seed;

(ii) obtain an encrypted EK by encrypting the EK using KEK;

(iii) store the encrypted EK in the DCD memory;

(iv) send the KEK to the KVD;

(v) generate a KEK identifier (“

KEK_ID”

) that identifies the KEK; and

(vi) store the KEK_ID in the DCD memory, wherein the DCD memory is accessible to an application resident on the DCD that accesses the data; and

(b) the KVD comprising a KVD memory and a KVD controller communicative with the KVD memory, the KVD memory having encoded thereon statements and instructions to cause the KVD controller to;

(i) receive the KEK from the DCD; and

(ii) store the KEK in the KVD memory.

41. The system of claim 40 wherein the DCD memory is further encoded to cause the DCD controller to generate the KEK, the EK, and the KEK_ID, and to delete the KEK from the DCD following encrypting the EK.

42. The system of claim 40 wherein the DCD memory is further encoded to cause the application to encrypt or decrypt the data by:

(a) obtaining the EK;

(b) encrypting or decrypting the data using the EK; and

(c) deleting the EK following encryption or decryption.

43. The system of claim 42 wherein obtaining the EK comprises:

(a) sending a request from the application for the EK, wherein the request comprises the KEK_ID;

(b) retrieving, from the KVD, the KEK that the KEK_ID identifies;

(c) decrypting, on the DCD, the EK encrypted using the KEK retrieved from the KVD; and

(d) sending the EK decrypted using the KEK to the application.

44. The system of claim 42 wherein obtaining the EK comprises:

(a) sending a request from the application for the EK, wherein the request comprises the KEK_ID;

(b) determining whether the EK is cached on the DCD; and

(c) when the EK is cached on the DCD, sending the EK that is cached on the DCD to the application.

45. The system of claim 40 wherein the DCD memory is further encoded to cause the DCD controller to safeguard the data by deleting one or both of the EK and KEK.

46. The system of claim 40 wherein the DCD comprises a memory stick.

47. The system of claim 40 wherein the DCD memory is further encoded to cause the EK and KEK to expire and to cause the DCD controller to replace the EK and KEK that expire with a different EK and a different KEK, respectively.

48. The system of claim 40 wherein the Bluetooth™

Low Energy protocol is used to link the KVD and DCD.

49. The system of claim 40 wherein the DCD memory is further configured to cause the DCD controller to:

(a) determine whether the KVD and DCD cease to be wirelessly linked; and

(b) delete the EK from the DCD when the KVD and DCD cease to be wirelessly linked.

50. The system of claim 40 wherein the DCD memory and KVD memory are further encoded to cause the DCD and KVD, respectively, to wirelessly pair with each other by:

(a) generating a weak shared secret key (“

WS2K”

) on the KVD and DCD;

(b) mutually authenticating the KVD and DCD to each other using the WS2K;

(c) following mutual authentication, generating a strong secure session key (“

S3K”

) on the KVD and DCD; and

(d) encrypting subsequent communications between the KVD and DCD using the S3K.

51. The system of claim 50 wherein the S3K expires and wherein the DCD memory and the KVD memory are further encoded to cause the DCD and KVD, respectively, to replace the S3K that expires with a different S3K.

52. The system of claim 50 wherein an Out of Bounds or Passkey Entry Bluetooth™

Low Energy association model is used to generate the WS2K.

53. The system of claim 40 further comprising:

(a) a key vault system manager (“

KVSM”

) wirelessly communicative with the KVD and DCD, the KVSM comprising a KVSM memory communicative with a KVSM controller, the KVSM memory having encoded thereon statements and instructions to cause the KVSM controller to receive device health information from the KVD and DCD,

wherein the DCD memory and the KVD memory are further encoded to cause the DCD controller and the KVD controller, respectively, to send device health information to the KVSM.

54. The system of claim 53 wherein the DCD memory and the KVD memory are further encoded to cause the DCD controller and the KVD controller, respectively, to:

(a) determine the health status of the DCD and the KVD, respectively, from the device health information; and

(b) delete the EK and KEK based on the health status.

55. The system of claim 53 wherein the KVSM memory is further encoded to cause the KVSM controller to:

(a) determine health statuses of the KVD and DCD from the device health information; and

(b) push the health statuses to the KVD and DCD,

wherein the DCD memory and the KVD memory are further encoded to cause the DCD controller and the KVD controller, respectively, to delete the EK and KEK based on one or more of the health status.

56. The system claim 53 wherein the DCD memory and the KVD memory are further encoded to back up the EK, KEK, and KEK_ID by pushing them to the KVSM.

57. The system of claim 40 wherein the DCD memory has stored thereon the EK encrypted using a public key having a linked private key, and wherein the DCD memory is further encoded to cause the DCD controller to:

(a) decrypt, using the private key, the EK encrypted using the public key;

(b) generate a new KEK, wherein the new KEK is not generated based on the user authentication secret;

(c) generate a new encrypted EK by encrypting the EK using the new KEK;

(d) store the new encrypted EK in the DCD memory; and

(e) send the new encrypted KEK to the KVD for storage.

58. The system of claim 40 wherein the EK and KEK are generated pseudorandomly.

59. A system for decoupling user authentication and data encryption on mobile devices, the system comprising a data container device (“

DCD”

) wirelessly linked to a key vault device (“

KVD”

), the DCD comprising a DCD memory and a DCD controller communicative with the DCD memory and the KVD comprising a KVD memory and a KVD controller communicative with the KVD memory, the DCD memory having encoded thereon statements and instructions to cause the DCD controller to;

(a) decrypt an encrypted encryption key (“

EK”

) stored in the DCD memory by;

(i) wirelessly retrieving from the KVD a key encryption key (“

KEK”

) used to encrypt the EK; and

(ii) decrypting the encrypted EK using the KEK;

(b) encrypt or decrypt data stored in the DCD memory using the EK, wherein neither the EK nor the KEK are generated using a user authentication secret as a seed;

(c) generate a KEK identifier (“

KEK_ID”

) that identifies the KEK; and

(d) store the KEK_ID in the DCD memory, wherein the DCD memory is accessible to an application resident on the DCD that accesses the data.

60. The system of claim 59 wherein the DCD memory is further encoded to cause DCD controller to delete the EK following encrypting or decrypting data.

61. The system of claim 59 wherein the DCD memory is further encoded to cause the DCD controller to:

(a) generate the EK and the KEK;

(b) obtain the encrypted EK by encrypting the EK using the KEK;

(c) store the encrypted EK in the DCD memory; and

(d) send the KEK to the KVD.

62. The system of claim 61 wherein the DCD memory is further encoded to cause the DCD controller to generate the KEK, the EK, and the KEK_ID, and to delete the KEK from the DCD following encrypting the EK.

63. The system of claim 61 wherein wirelessly retrieving the KEK from the KVD comprises:

(a) sending a request for the KEK_ID from the DCD to the KVD, wherein the request comprises the KEK_ID; and

(b) sending the KEK that the KEK_ID identifies from the KVD to the DCD.

64. The system of claim 59 wherein the DCD memory is further encoded to cause the DCD controller to safeguard the data by deleting one or both of the EK and KEK.

65. The system of claim 59 wherein the DCD comprises a memory stick.

66. The system of claim 59 wherein the DCD memory is further encoded to cause the EK and KEK to expire and to cause the DCD controller to replace the EK and KEK that expire with a different EK and a different KEK, respectively.

67. The system of claim 59 wherein the Bluetooth™

Low Energy protocol is used to link the KVD and DCD.

68. The system of claim 59 wherein the DCD memory is further configured to cause the DCD controller to:

(a) determine whether the KVD and DCD cease to be wirelessly linked; and

(b) delete the EK from the DCD when the KVD and DCD cease to be wirelessly linked.

69. The system of claim 59 wherein the DCD memory and KVD memory are further encoded to cause the DCD and KVD, respectively, to wirelessly pair with each other by:

(a) generating a weak shared secret key (“

WS2K”

) on the KVD and DCD;

(b) mutually authenticating the KVD and DCD to each other using the WS2K;

(c) following mutual authentication, generating a strong secure session key (“

S3K”

) on the KVD and DCD; and

(d) encrypting subsequent communications between the KVD and DCD using the S3K.

70. The system of claim 69 wherein the S3K expires and wherein the DCD memory and the KVD memory are further encoded to cause the DCD and KVD, respectively, to replace the S3K that expires with a different S3K.

71. The system of claim 69 wherein an Out of Bounds or Passkey Entry Bluetooth™

Low Energy association model is used to generate the WS2K.

72. The system of claim 59 further comprising:

(a) a key vault system manager (“

KVSM”

) wirelessly communicative with the KVD and DCD, the KVSM comprising a KVSM memory communicative with a KVSM controller, the KVSM memory having encoded thereon statements and instructions to cause the KVSM controller to receive device health information from the KVD and DCD,

wherein the DCD memory and the KVD memory are further encoded to cause the DCD controller and the KVD controller, respectively, to send device health information to the KVSM.

73. The system of claim 72 wherein the DCD memory and the KVD memory are further encoded to cause the DCD controller and the KVD controller, respectively, to:

(a) determine the health status of the DCD and the KVD, respectively, from the device health information; and

(b) delete the EK and KEK based on the health status.

74. The system of claim 72 wherein the KVSM controller is further encoded to cause the KVSM controller to:

(a) determine health statuses of the KVD and DCD from the device health information; and

(b) push the health statuses to the KVD and DCD,

wherein the DCD memory and the KVD memory are further encoded to cause the DCD controller and the KVD controller, respectively, to delete the EK and KEK based on one or more of the health status.

75. The system of claim 72 wherein the DCD memory and the KVD memory are further encoded to back up the EK, KEK, and KEK_ID by pushing them to the KVSM.

76. The system of claim 59 wherein the DCD memory has stored thereon the EK encrypted using a public key having a linked private key, and wherein the DCD memory is further encoded to cause the DCD controller to:

(a) decrypt, using the private key, the EK encrypted using the public key;

(b) generate a new KEK, wherein the new KEK is not generated based on the user authentication secret;

(c) generate a new encrypted EK by encrypting the EK using the new KEK;

(d) store the new encrypted EK in the DCD memory; and

(e) send the new encrypted KEK to the KVD for storage.

77. The system of claim 59 wherein the EK and KEK are generated pseudorandomly.

78. A non-transitory computer readable medium having encoded thereon statements and instructions to cause a controller to:

(a) generate an encryption key (“

EK”

) for encrypting data and a key encryption key (“

KEK”

) for encrypting the EK, wherein neither the EK nor the KEK are generated using a user authentication secret as a seed;

(b) obtain an encrypted EK by encrypting the EK using the KEK;

(c) store the encrypted EK on a data container device (“

DCD”

);

(d) store the KEK on a key vault device (“

KVD”

) that is distinct from the DCD;

(e) generating a KEK identifier (“

KEK_ID”

) that identifies the KEK; and

(f) storing the KEK_ID in memory accessible to an application resident on the DCD that accesses the data and on the KVD.

79. A non-transitory computer readable medium having encoded thereon statements and instructions to cause a controller to:

(a) decrypt an encrypted encryption key (“

EK”

) stored on a data container device (“

DCD”

) by;

(i) wirelessly retrieving to the DCD from a key vault device (“

KVD”

) a key encryption key (“

KEK”

) used to encrypt the EK; and

(ii) decrypting the encrypted EK using the KEK;

(b) encrypt or decrypt data stored on the DCD using the EK, wherein neither the EK nor the KEK are generated using a user authentication secret as a seed;

(c) generating a KEK identifier (“

KEK_ID”

) that identifies the KEK; and

(d) storing the KEK_ID in memory accessible to an application resident on the DCD that accesses the data and on the KVD.