Patent ID: 7937759

Claim:
A communication device protected from denial of services attacks, comprising: a network interface configured to establish a communication session between the communication device and a remote device; and communication logic stored on the communication device, wherein executing the communication logic on the communication device causes the communication device to: share a first random value with the remote device in response to establishing the communication session with the remote device, wherein the communication device transmits the first random value to the remote device over the network interface; calculate a first access filter value from the first random value using one or more secrets shared with the remote device; receive a first message frame that includes a first unencrypted hash value and a second random value from the remote device, wherein the remote device calculates the first unencrypted hash value from the first random value using the one or more shared secrets, and wherein the remote device uniquely calculates a second access filter value for the communication device from the second random value using the one or more shared secrets; authenticate the first message frame received from the remote device in response to the first unencrypted hash value in the first message frame matching the first access filter value uniquely calculated for the remote device; calculate a second hash value from the second random value in the first message frame received from the remote device using the one or more shared secrets; and transmit a second message frame that includes the second hash value to the remote device, wherein the remote device authenticates the second message frame in response to the second hash value in the second message frame matching the second access filter value uniquely calculated for the communication device at the remote device.