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LoRa Backscatter [pdf]

homes.cs.washington.edu

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Re: LoRa Backscatter [pdf]

#21

Post by vanderZwan »

inanutshellus wrote: post #15

"Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway." —Tanenbaum, Andrew S. (1989).

A more up-to-date take on this:

> Games on Disc More Energy Efficient than Downloads

http://www.notechmagazine.com/2014/09/games-on-disc-more-ene...

And if you really want to dive into the complications of this topic from a broader perspective of energy use, this piece is full of thought-provoking questions, even if you don't necessarily agree with the conclusions:

http://www.lowtechmagazine.com/2015/10/can-the-internet-run-...

Re: LoRa Backscatter [pdf]

#22

Post by donohoe »

I worry about encryption of sensitive data.

I don't doubt it can be done, but can their "twenty-cent" chip handle it without messing up its lightweight low-power nature?

Re: LoRa Backscatter [pdf]

#23

Post by sohkamyung »

baccredited wrote: post #12
stickfigure wrote: post #6

Earlier quoted context omitted.

Disable Javascript for that site and it reads normally. I've found that most news sites become much more readable (and chew through far less of my CPU, and stop autoplaying loud videos, and skip paywalls) with JS disabled. The Chrome plugin I'm using (Quick Javascript Switcher) disables on a per-domain basis and remembers the setting for each. I'm a huge fan of SPAs and JS in the browser and yet I'm quickly blocking…

YesScript worked for me on Firefox. Thanks for the idea. https://addons.mozilla.org/en-US/firefox/addon/yesscript/dev...

Just a note that YesScript isn't compatible with my Firefox Nightly now (due to the move to WebExtensions) and will probably stop working with Firefox in general in the future.

Re: LoRa Backscatter [pdf]

#24

Post by junkcollector »

miekw wrote: post #20

Here's the paper: https://homes.cs.washington.edu/~gshyam/Papers/loRaBackscatt... Tech like this already exists (look up "UHF RFID") and the picture they've got looks very similar to existing tags (image search for "alien rfid tag"). The interesting thing here is managing to implement LoRa's modulation scheme in a passive tag.

It's not a passive tag. If you only read 3 sentences into the abstract, you find out that it is an active device. This is repeated at the end of the abstract and right at the beginning of page 2 in the introduction.

Re: LoRa Backscatter [pdf]

#25

Post by junkcollector »

donohoe wrote: post #22

I worry about encryption of sensitive data. I don't doubt it can be done, but can their "twenty-cent" chip handle it without messing up its lightweight low-power nature?

Modern microcontrollers can be had in the sub-$5 range that support hardware implemented encrypting algorithms. Mostly it's a worthless feature but we aren't far out from it being more or less standard even in the $0.20 guys.

The bigger issue is that the entire point of this system is to remove cost of deployment and maintenance for cheap highly distributed lo-fi systems. The cost of keying all those devices for encryption would defeat the purpose. Also the added data overhead of the encryption would possibly exceed the amount of actual data you are trying to get out of the system. Also, why do you even want to encrypt it in the first place?

Re: LoRa Backscatter [pdf]

#26

Post by pjc50 »

junkcollector wrote: post #25
donohoe wrote: post #22

I worry about encryption of sensitive data. I don't doubt it can be done, but can their "twenty-cent" chip handle it without messing up its lightweight low-power nature?

Modern microcontrollers can be had in the sub-$5 range that support hardware implemented encrypting algorithms. Mostly it's a worthless feature but we aren't far out from it being more or less standard even in the $0.20 guys. The bigger issue is that the entire point of this system is to remove cost of deployment and maintenance for cheap highly distributed lo-fi systems. The cost of keying all those devices for encr…

The Economist article for the same subject suggested using this in medical devices.

One-time keying may not be as expensive as you think, a simple matter of IC fuses, but you're right that key management and "enrolment" generally for these tiny things will be a pain.

Re: LoRa Backscatter [pdf]

#27

Post by wyager »

junkcollector wrote: post #25
donohoe wrote: post #22

I worry about encryption of sensitive data. I don't doubt it can be done, but can their "twenty-cent" chip handle it without messing up its lightweight low-power nature?

Modern microcontrollers can be had in the sub-$5 range that support hardware implemented encrypting algorithms. Mostly it's a worthless feature but we aren't far out from it being more or less standard even in the $0.20 guys. The bigger issue is that the entire point of this system is to remove cost of deployment and maintenance for cheap highly distributed lo-fi systems. The cost of keying all those devices for encr…

> Also, why do you even want to encrypt it in the first place?

I want to encrypt and authenticate any and all wireless gadget data because I've been paying attention to the last 5 years of defcon talks.

Re: LoRa Backscatter [pdf]

#29

Post by junkcollector »

pjc50 wrote: post #26
junkcollector wrote: post #25

Earlier quoted context omitted.

Modern microcontrollers can be had in the sub-$5 range that support hardware implemented encrypting algorithms. Mostly it's a worthless feature but we aren't far out from it being more or less standard even in the $0.20 guys. The bigger issue is that the entire point of this system is to remove cost of deployment and maintenance for cheap highly distributed lo-fi systems. The cost of keying all those devices for encr…

The Economist article for the same subject suggested using this in medical devices. One-time keying may not be as expensive as you think, a simple matter of IC fuses, but you're right that key management and "enrolment" generally for these tiny things will be a pain.

Medical is just an example of the economist not understanding the product vs the buzzline. It is a terrible tech implementation for medical, but I agree that you generally want medical encrypted. However, if you are talking medical, the cost of the sensor device is tiny compared to other costs even for very expensive sensors.

Fuse based programming would have a whole host of issues. You either need a destructive fill device or load at the factory. If you load at the factory you have to trust them to not retain copies, keeping in mind that it will probably me manufactured in China. If you use a fill device you open up for destructive programming (IC fuses) you open up a bunch of liability for accidental damage to the device plus the cost of a technician plus training can quickly swamp out the cost of your low cost sensor network.

Finally, these sorts of networks work best with asynchronous uni-diretional communication applications. This makes good crypto-practices very difficult. If you chose full crypto and handshake protocols, the amount of data you spend just exchanging keys and handshakes will exceed the data the sensors collect.

Re: LoRa Backscatter [pdf]

#30

Post by isp »

asteinbr wrote: post #28

Which font is used in the document?

Linux Libertine: https://en.wikipedia.org/wiki/Linux_Libertine

  $ pdffonts loRaBackscatter.pdf
  
  name                                 type              emb sub uni object ID
  ------------------------------------ ----------------- --- --- --- ---------
  OZJJTN+LinBiolinumTB                 Type 1            yes yes yes    116  0
  LWEMPN+LinBiolinumT                  Type 1            yes yes yes    118  0
  LWEMPN+LinBiolinumT                  Type 1            yes yes yes    119  0
  LILBVD+LinLibertineT                 Type 1            yes yes yes    120  0
  LILBVD+LinLibertineT                 Type 1            yes yes yes    121  0
  ...
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