Friendly channel-oblivious jamming with error amplification for wireless networks

Privacy has become a major concern in wireless networks, especially in networks with weak or no password protection. While it has been proposed to send jamming signals to thwart the reception of the eavesdropper, the jamming signal typically cannot introduce enough errors to cover the entire packet when the jamming signal is not very strong, mainly due to the use of error correction codes in the system. Fortunately, error amplifiers can be easily constructed using block ciphers to amplify and spread the errors without requiring any secret keys. With error amplification, the jamming strategy needs to be revisited, because introducing a few errors is sufficient protect the privacy of the entire packet, instead of having to jam the entire packet. We propose a novel jamming strategy, called jMax, with proven performance bounds to the optimal jamming signal power. The idea of jMax is to rotate jamming vectors such that the jamming power can be maximized when the jamming vector close to the optimal jamming vector is used. We collect real-world CSI data with the Intel 5300 wireless card and use the Microsoft Sora Software-Defined Radio to process jammed data packets. Our results show that jMax achieves significant gains over other approaches.