Patents Assigned to Data Encryption Systems Limited
  • Patent number: 7471796
    Abstract: A security system for controlling access to encrypted information, comprising: a memory for storing at least one decryption key for use in decrypting an encrypted item of information, the decryption key being associated with a security code which can be used to determine whether the security system is authorized to send encrypted copies of the decryption key to others. If the security system is authorized to send an encrypted copy of the decryption key, it encrypts the decryption key and propagates the encrypted copy of the decryption key. Each time the security system propagates a decryption key, it includes as part of the decryption key an identifier indicating the identity of a sender's key. A user can append a control word against their identity in the decryption key to instruct the security system to initiate a message to them or an agent informing them of the propagation of the key and giving information concerning that propagation.
    Type: Grant
    Filed: July 20, 2006
    Date of Patent: December 30, 2008
    Assignee: Data Encryption Systems Limited
    Inventor: David Robin Tomlinson
  • Patent number: 7099478
    Abstract: An apparatus for and method of controlling propagation of decryption keys is provided. One embodiment of the present invention includes an encryption key propagation control system wherein a generation number is identified with each decryption key and the generation number is queried each time a request is made to forward the decryption key to another user. The generation number is decremented at each request, and once it reaches zero, further requests are refused by the control system.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: August 29, 2006
    Assignee: Data Encryption Systems Limited
    Inventor: David Robin Tomlinson