Thwarting traffic analysis

Abstract

A wireless communication device capable of operating according to a wireless communication protocol and capable of operating in a mesh network, the device being configured to: at a first time transmit data packets in accordance with a mesh network protocol; determine an activity profile that characterises the pattern of transmission of those data packets from the communication device; and subsequently transmit dummy data packets in accordance with the mesh network protocol so as to adopt an activity profile that mimics the determined activity profile.

What is claimed is: 
     
         1 . A wireless communication device capable of operating according to a wireless communication protocol and capable of operating in a mesh network, the device being configured to:
 at a first time transmit data packets in accordance with a mesh network protocol;   determine an activity profile that characterises the pattern of transmission of those data packets from the communication device; and   subsequently transmit dummy data packets in accordance with the mesh network protocol so as to adopt an activity profile that mimics the determined activity profile.   
     
     
         2 . A wireless communication device as claimed in  claim 1 , wherein the determined activity profile specifies a number of data packets to be transmitted over a time period according to the characterisation. 
     
     
         3 . A wireless communication device as claimed in  claim 2 , wherein the activity profile delineates the transmission of data packets over a period of time according to the characterisation. 
     
     
         4 . A wireless communication device as claimed in  claim 3 , wherein the device is configured to characterise the transmission of data packets as an average such that the determined activity profile is an average transmission profile. 
     
     
         5 . A wireless communication device as claimed in  claim 4 , wherein the device is configured to determine the average transmission profile from a plurality of transmission profiles each delineating the transmission of data packets over a period of time. 
     
     
         6 . A wireless communication device as claimed in  claim 3 , wherein the device is configured to characterise the transmission of the data packets as a mode such that the determined activity profile is a modal transmission profile. 
     
     
         7 . A wireless communication device as claimed in  claim 6 , wherein the device is configured to determine the modal transmission profile from a plurality of transmission profiles each delineating the transmission of data packets over a period of time. 
     
     
         8 . A wireless communication device as claimed in  claim 1 , wherein the device is configured to operate according to the Bluetooth Low Energy protocol and wherein the mesh network is an ad-hoc network. 
     
     
         9 . A wireless communication device as claimed in  claim 1 , wherein the device is configured to transmit dummy packets in a form indicative of a request for an acknowledgement. 
     
     
         10 . A wireless communication device as claimed in  claim 9 , wherein the device is configured to transmit an acknowledgement in response to receiving a data packet similar to said dummy packets indicative of a request for acknowledgement. 
     
     
         11 . A wireless communication device as claimed in  claim 1 , wherein the device is configured to transmit at least some data packets configured to control and/or monitor the state of remote objects within the mesh network during the first time. 
     
     
         12 . A wireless communication device as claimed in  claim 1 , wherein the device is configured to exclusively transmit data packets configured to control and/or monitor the state of remote objects within the mesh network during the first time. 
     
     
         13 . A wireless communication device capable of operating according to a wireless communication protocol and capable of operating in a mesh network, the device being configured to:
 at a first time transmit data packets of a first type in accordance with a mesh network protocol to control and/or monitor the state of remote devices within the mesh network; and   transmit, independently of the transmission of the first type of data packets, dummy data packets in accordance with the mesh network protocol so as to obscure a variation in transmission of the first type of data packets from the first time.   
     
     
         14 . A wireless communication device as claimed in  claim 13 , wherein the device is configured to transmit the dummy data packets according to a desired transmission profile, wherein the desired transmission profile delineates the desired transmission of data packets from the wireless communication device over a period of time. 
     
     
         15 . A wireless communication device as claimed in  claim 14 , wherein the device is configured to determine an activity profile that characterises the transmission of the first type of data packets during the first time. 
     
     
         16 . A wireless communication device as claimed in  claim 15 , wherein the device is configured to characterise the transmission of the first type of data packets as one of: (i) an average such that the activity profile Is an average transmission profile or (ii) a mode such that the activity profile is a modal transmission profile. 
     
     
         17 . A wireless communication device as claimed in  claim 15 , wherein the determined activity profile has an associated average transmission rate and wherein the desired transmission profile has an associated average transmission rate that is substantially higher than the average transmission rate of the activity profile. 
     
     
         18 . A wireless communication device as claimed in  claim 14 , wherein the device is configured to transmit the dummy data packets according to the desired transmission profile at an average transmission rate that is high enough so as to obscure a variation in transmission of the first type of data packets from the first time. 
     
     
         19 . A wireless communication device as claimed in  claim 13 , wherein the device is configured to transmit the dummy data packets in a pseudo-random manner at an average rate high enough so as to obscure a variation in transmission of the first type of data packets from the first time. 
     
     
         20 . A wireless communication device as claimed in  claim 13 , wherein the device operates according to the Bluetooth Low Energy protocol and wherein the mesh network is an ad-hoc network.