SYSTEM AND METHOD OF ENFORCING A COMPUTER POLICY

• US 20130159704A1
• Filed: 01/11/2011
• Published: 06/20/2013
• Est. Priority Date: 01/11/2010
• Status: Active Grant

• Current Assignee: Scentrics Information Security Technologies Ltd.
• Original Assignee: Scentrics Information Security Technologies Ltd.
• Inventors: Chandrasekaran, Guruparan
• Granted Patent: US 10,122,529 B2
• Time in Patent Office: Days
• US Class Current: 713/156
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: H04L 2209/127 Trusted platform modules [TPM]
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/102 Entity profiles
• CPC Class Codes: H04L 9/08 Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords network architectures or network communication protocols for supporting key management in a packet data network H04L63/06
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• 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 9/0891 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

Abstract

A method and system of enforcing a computer policy uses a central server to manage user profiles, policies and encryption keys. The server securely supplies the keys to client devices only after checking that the policy has been complied with. The checks include both the identity of the user and the machine identity of the client device. The keys are held in a secure environment of the client device, for example in a Trusted Platform Module (TPM), and remain inaccessible at all times to the end user. Theft or loss of a portable client device does not result in any encrypted data being compromised since the keys needed to decrypt that data are not extractable from the secure environment.

Claims

1. A method of accessing a cryptographic key stored on a remote server in order to perform a cryptographic operation, comprising:

determining the identity of a user;

cryptographically validating the identity of the client device;

determining whether the identity of the user and the identity of the client device satisfy an access condition which is stored on the remote server;

securely transmitting the cryptographic key from the remote server to the client device when the access condition is satisfied; and

using the cryptographic key to perform a cryptographic operation without disclosing the cryptographic key to the user.

41. The method of claim 1, wherein the cryptographic operation comprises signing data.

42. The method of claim 1, comprising using a secure cryptoprocessor to allow the client device'"'"'s identity to be cryptographically validated or to perform the cryptographic operation.

43. The method of claim 1, further comprising the client device holding the cryptographic key in volatile memory and clearing the cryptographic key from the memory after performing the cryptographic operation.

44. The method of claim 1, further comprising the server validating the identity of the client device.

45. The method of claim 1, further comprising the server verifying the identity of the user.

46. The method of claim 1, further comprising the client device validating the identity of the server.

47. The method of claim 1, wherein the cryptographic key is specific to the user.

48. The method of claim 1, further comprising the remote server transmitting one or more certificates along with the cryptographic key.

2-40. -40. (canceled)

49. A client device configured to:

allow the device'"'"'s identity to be cryptographically validated;

receive a securely-transmitted cryptographic key from a remote server; and

use the cryptographic key to perform a cryptographic operation without disclosing the cryptographic key to a user

50. The client device of claim 49, wherein the cryptographic operation comprises signing data.

51. The client device of claim 49, comprising a secure cryptoprocessor.

52. The client device of claim 51, wherein the secure cryptoprocessor comprises a Trusted Platform Module.

53. The client device of claim 51, configured to use the secure cryptoprocessor to allow the client device'"'"'s identity to be cryptographically validated or to perform the cryptographic operation.

54. The client device of claim 49, further configured to hold the cryptographic key in volatile memory and to clear the cryptographic key from the memory after performing the cryptographic operation.

55. The client device of claim 49, further configured to validate the identity of the server.

56. A server on which a cryptographic key and an access condition are stored, wherein the server is configured to:

determine whether the identity of a user and the identity of a client device satisfy the access condition; and

transmit the cryptographic key securely to the client device when the access condition is satisfied.

57. The server of claim 56, further configured to validate the identity of the client device.

58. The server of claim 56, further configured to verify the identity of the user.

59. The server of claim 56, further configured to transmit one or more certificates along with the cryptographic key.