xref: /openwifi/doc/app_notes/csi_fuzzer.md (revision b49db4c59a0f2511208515d878ea297c204de6d1) 
1<!--
2Author: Xianjun jiao
3SPDX-FileCopyrightText: 2021 UGent
4SPDX-License-Identifier: AGPL-3.0-or-later
5-->
6
7CSI (Channel Station Information) of WiFi systems is available in some WiFi chips and can be used for environment (people, object, activity) sensing passively and secretly.
8
9How could a CSI fuzzer stop unauthorized sensing?
10
11![](./csi-fuzzer-system-before-vs-now.png)
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13CSI fuzzer implementation principle.
14
15![](./csi-fuzzer-principle.png)
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17CSI fuzzer in openwifi system architecture and related commands.
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19![](./csi-fuzzer-implementation.png)
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21Thanks 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 the self-monitoring, the auto-mute during Tx needs to be disabled:
22
23```
24./sdrctl dev sdr0 set reg xpu 1 1
25```
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27CSI self-monitoring before fuzzing.
28
29![](./csi-fuzzer-beacon-ant-back-0.jpg)
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31CSI self-monitoring after  fuzzing command: `csi_fuzzer.sh 1 45 0 13`
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33![](./csi-fuzzer-beacon-ant-back-1-45-0-13.jpg)
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35`csi_fuzzer_scan.sh` can scan the c1 and c2 in different styles/modes by calling `csi_fuzzer.sh`.
36