When Wifi goes down: Transfer files from Air gapped machines using QR codes

Posted by vinnyglennon on Friday April 22, 2016 @08:10AM
from the github.com dept.

( 4 comments | 5 points | on HN )

Re:When Wifi goes down: Transfer files from Air gapped machi... by padde on Friday April 22, 2016 @11:39AM (#11549972)

This is cool.

I guess with high density QR codes, a decent display and a good cam you could transfer a megabyte or more in a minute :D If both devices have front facing cameras, such as smartphones, you could even have a real-time back channel (duplex), and the receiving device could signal the sending device that a certain "frame" got lost and needs to be retransmitted.

[ Parent | on HN ]

Re:When Wifi goes down: Transfer files from Air gapped machi... by coreyp_1 on Friday April 22, 2016 @08:28AM (#11548592)

This is a beautiful idea. How much information does the QR code carry, and how much is transfer boilerplate?

[ Parent | on HN ]

Re:When Wifi goes down: Transfer files from Air gapped machi... by th0br0 on Friday April 22, 2016 @11:37AM (#11549955)

The maximum storage capacity seems to be 2953 bytes ([1]). Although that's with error correction level L, so you can only read it as long as you have 93% of all codewords.

[1] https://en.wikipedia.org/wiki/QR_code#Storage

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Re:When Wifi goes down: Transfer files from Air gapped machi... by leonjza on Friday April 22, 2016 @09:15AM (#11548854)

Author here. The amount of data per QR depends on the QR size specified. If I remember correctly, its about 10 bytes per code in the default config (QR code size of 30). Transfer boilerplate is a few codes in the start to setup the conversation and a FIN like message at the end.

[ Parent | on HN ]