Side channel analysis attacks against channel state information based key generation

The recent research on randomness of wireless channels shows that the channel state information (CSI) can be harnessed to generate secret keys for wireless communications. This CSI-based key generation claims to be secure due to the spatial independence between the legitimate channel and the eavesdropping channel. However, this paper presents the discovery that the side-channel information about the security key may leak from the electronic instruments when they are measuring the CSI, when the instruments are encrypting/decrypting for key confirmation, or even when the device is communicating with the established key. Through analyzing the side-channel information, the secret keys can be extracted. The side-channel information could be obtained without approaching the legitimate transceiver, thus posing a serious threat to the CSI-based key generation.