A Product Channel Attack to Wireless Physical Layer Security

We propose a novel attack that compromises the physical layer security in wireless systems with eavesdropper's channel state information at the transmitter side. This technique is based on the transmission of a slowly-varying random symbol by the eavesdropper during its uplink transmission, so that the equivalent fading channel observed at the base station (BS) has a larger variance. Then, the BS designs the secure downlink transmission under the assumption that the eavesdropper's channel experiences a larger fading severity than in reality. We show that this approach can lead the BS to transmit to Bob at a rate larger than the secrecy capacity, thus compromising the system secure operation. Our analytical results, corroborated by simulations, show that the use of multiple antennas at the BS may partially alleviate but not immunize against these type of attacks.

Automated summary

The proposed attack compromises physical layer security in wireless systems by transmitting slowly-varying random symbols to increase the fading severity observed at the base station, leading to transmission to Bob at a rate larger than the secrecy capacity. Using multiple antennas at the base station may partially alleviate but not immunize against these attacks.