[ACM WiSec 2021. Openwifi CSI fuzzer for authorized sensing and covert channels](https://dl.acm.org/doi/pdf/10.1145/3448300.3468255) CSI (Channel State Information) of WiFi systems is available in some WiFi chips and can be used for sensing the environment (keystrokes, people, object) passively and secretly. ## Concept How could a CSI fuzzer stop unauthorized sensing?  CSI fuzzer implementation principle.  ## Demo instructions Thanks to the full-duplex capability and CSI extraction feature of openwifi, you can monitor the artificial channel response via [side channel](./csi.md) by Tx-Rx over the air coupling without affecting the normal operation/traffic of openwifi. Before fuzzing the CSI, please follow [WiFi CSI radar via self CSI capturing](radar-self-csi.md) app note to setup normal self CSI monitoring. Then, start another ssh session to the openwifi board: ``` ssh root@192.168.10.122 (password: openwifi) cd openwifi ./csi_fuzzer_scan.sh 1 (CSI fuzzer applies possible artificial CSI by scanning all values) (csi_fuzzer.sh is called. Please read both scripts to understand these commands) ``` Now you should see that CSI keeps changing like in this [video](https://youtu.be/aOPYwT77Qdw). # Further explanation on parameters CSI fuzzer in openwifi system architecture and related commands.  # Example fuzzed CSI CSI self-monitoring before fuzzing.  CSI self-monitoring after fuzzing command: `./csi_fuzzer.sh 1 45 0 13`  `csi_fuzzer_scan.sh` can scan the c1 and c2 in different styles/modes by calling `csi_fuzzer.sh`.