
Passive Wi-Fi: Bringing Low Power to Wi-Fi Transmissions - godelmachine
https://www.usenix.org/conference/nsdi16/technical-sessions/presentation/kellogg
======
ourcat
There's been a few links regarding WiFi backscatter use around here recently.

Connecting RF-Powered Devices to the Internet :
[http://iotwifi.cs.washington.edu/](http://iotwifi.cs.washington.edu/)

3-D printed objects connect to WiFi without electronics :
[http://www.washington.edu/news/2017/12/05/in-
first-3-d-print...](http://www.washington.edu/news/2017/12/05/in-
first-3-d-printed-objects-connect-to-wifi-without-electronics/)

~~~
John_KZ
I also remember an article about a very low power camera performing read
operations in an analog way with no onboard power. I think. I can't find the
article though.

Also there was [https://github.com/seemoo-
lab/mobisys2018_nexmon_software_de...](https://github.com/seemoo-
lab/mobisys2018_nexmon_software_defined_radio).

If you think about it, there are a lot more things that can be done with wifi
if you can arbitrarily TX/RX signals. In fact I'm getting a bit scared now.

~~~
awelkie
You may be thinking of this article:
[https://news.ycombinator.com/item?id=16881946](https://news.ycombinator.com/item?id=16881946)

~~~
John_KZ
Yes, this is it.

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simpsond
This seems to require a near-by powered wifi device to aide in association of
the passive device. For large deployments, that would require many powered
units. In addition to that, there are requirements for multiple MACs, which
may also lead to problems with limits in some networks. This is all clever,
but it doesn't seem practical to me since the passive device depends on a near
by powered device to do anything. I have worked on sensor networks with
battery powered wifi devices. It's certainly tricky.

~~~
emilfihlman
>This seems to require a near-by powered wifi device to aide in association of
the passive device.

...Yes? Gateways (routers) are there anyways.

>For large deployments, that would require many powered units.

As in all deployments?

>In addition to that, there are requirements for multiple MACs, which may also
lead to problems with limits in some networks.

Wot? This is a non issue.

>This is all clever, but it doesn't seem practical to me since the passive
device depends on a near by powered device to do anything. I have worked on
sensor networks with battery powered wifi devices. It's certainly tricky.

Then you don't understand what this is about.

Backscatter is awesome because you literally don't put energy into generating
rf yourself.

------
ComodoHacker
>View the slides

Can't we have PDF.js decode and render .pptx files? I bet they're no more
complex than PDF.

~~~
Doxin
You're betting wrong. The office formats are horrifically complex.

------
godelmachine
Is this system not susceptible to over-the-air attacks by malicious
adversaries?

~~~
oh_sigh
And why's it always malicious adversaries? Why can't we ever get some
benevolent adversaries around here?

~~~
yjftsjthsd-h
People want to defend against the latest threat.

Now, what on earth is a benevolent adversary?

~~~
jobigoud
I thought of something else that is not discussed often. There is a class of
actors that can do good actions with bad ulterior motives.

For example in France we had a group of anti-muslim people provide free food
to the homeless but the food had specifically pork in it.

Or linked to a recent HN story a vegan terrorist could infect himself with
that tick that renders you allergic to meat and then go donate blood for
saving children.

~~~
michaelmior
Those are really interesting examples although obviously stretching the
definition of "benevolent."

------
godelmachine
Research Paper ->
[https://news.ycombinator.com/item?id=17053300](https://news.ycombinator.com/item?id=17053300)

