Patents by Inventor Christian Martin Gehrmann

Christian Martin Gehrmann has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8209550
    Abstract: The teachings herein present a method and apparatus for protecting usage restriction data that governs usage of an electronic device. A cryptographic circuit supports secure and non-secure accesses. When non-securely accessed, it is operable only to verify the stored usage restriction data, and, when securely accessed, it is operable to generate a new message authentication code for changed usage restriction data, for subsequent authentication of that data. The usage restriction data may be stored in non-secure memory and may include static and dynamic parts. One or more embodiments include a secure circuit indicating whether the device has been initialized. The cryptographic circuit outputs a message authentication code for the static part using a permanent device key from the secure circuit, only if the device has not been initialized, and outputs a message authentication code for the dynamic part as needed to support authorized changes to the dynamic part.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: June 26, 2012
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventor: Christian Martin Gehrmann