Patent ID: 8015413
Filing Date: 2011-09-06
Classification: H04L

Abstract:
1. A method of communicating a communication fragment, the communication fragment comprising a target group address referring to at least two receiver devices, the method comprising acts of: a sender device adding a cryptographic message integrity code forming a protected communication fragment to protect at least part of the communication fragment, wherein the cryptographic message integrity code is at least partly based on the target group address; the sender device transmitting the protected communication fragment to at least one receiver device through use of a router device that is not part of a trusted group to which the sender device and the at least one receiver device belong; the router device, for the at least one receiver device referred to in the target group address, replacing the target group address with an address of the at least one receiver device forming a modified protected communication fragment, while maintaining the unchanged cryptograph message integrity code, and subsequently forwarding the modified protected communication fragment to the at least one receiver device; the at least one receiver device receiving the modified protected communication fragment; and the at least one receiver device restoring the original protected communication fragment by replacing the address of the at least one receiver device with the target group address to allow verification of the protected communication fragment using the message integrity code.