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Decimen Optical Transfer: fountain-coded QR file transfer

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Re: Decimen Optical Transfer: fountain-coded QR file transfer

#31

Post by elric »

utopiah wrote: post #13
elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

Indeed encryption should not be hard yet which situation do you have in mind where simply pulling away the emitting phone would not be enough? AFAIK the normal scenario is two persons in the same physical space so I am not sure what encryption would add.

Other cameras could presumably be snooping on the data transfer.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#32

Post by throwaway260626 »

pjc50 wrote: post #29
elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

> between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago Airdrop is a thing, but remember that Android phones are controlled by the online services company that wants you to use online services.

Bluetooth is a thing too and I think it is even faster than this qr code video transfer method. Of course still slower than Airdrop.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#33

Post by inigyou »

myself248 wrote: post #21
legulere wrote: post #15

The actual article explaining the use for fountain codes in this use case: https://divan.dev/posts/fountaincodes/

Oooooooooooo. I bet that's how satellite radios get their firmware updates and stuff. Actually I bet it's how they get almost everything aside from the audio streams themselves. Metadata. Channel art. Subscription info. Traffic data. Weather maps. Receiver firmware... The satellite is a textbook-perfect fountain, and the receiver may tune in at any time during the stream, and may miss any random number of packets, bu…

I bet they don't, because they didn't know about it or didn't think of it.

I know GPS is a slow repeating stream (the ephemeris repeats every 30 seconds and the almanac every 12.5 minutes) but that probably came before fountain codes.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#34

Post by inigyou »

pjc50 wrote: post #29
elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

> between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago Airdrop is a thing, but remember that Android phones are controlled by the online services company that wants you to use online services.

Actually it's the opposite - Airdrop is controlled by the vendor lock-in company that wants you to only buy its hardware.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#35

Post by inigyou »

elric wrote: post #31
utopiah wrote: post #13

Earlier quoted context omitted.

Indeed encryption should not be hard yet which situation do you have in mind where simply pulling away the emitting phone would not be enough? AFAIK the normal scenario is two persons in the same physical space so I am not sure what encryption would add.

Other cameras could presumably be snooping on the data transfer.

They could, you're right.

Usability is important though. If you have to type in a bunch of hex digits before sending, it won't be used.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#37

Post by [deleted] »

elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

[deleted]

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#38

Post by utopiah »

elric wrote: post #31
utopiah wrote: post #13

Earlier quoted context omitted.

Indeed encryption should not be hard yet which situation do you have in mind where simply pulling away the emitting phone would not be enough? AFAIK the normal scenario is two persons in the same physical space so I am not sure what encryption would add.

Other cameras could presumably be snooping on the data transfer.

Realistically speaking with another phone in front and imagining how close one has to be for it to work reliably (as it is not a 64x64 pixels image) I think it would be really hard not to notice.

The same way you whisper to say something secret in a public space I would expect people who transfer something private in public would have the presence of mind not let other snoop on and react accordingly.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#39

Post by cwmoore »

inigyou wrote: post #33
myself248 wrote: post #21

Earlier quoted context omitted.

Oooooooooooo. I bet that's how satellite radios get their firmware updates and stuff. Actually I bet it's how they get almost everything aside from the audio streams themselves. Metadata. Channel art. Subscription info. Traffic data. Weather maps. Receiver firmware... The satellite is a textbook-perfect fountain, and the receiver may tune in at any time during the stream, and may miss any random number of packets, bu…

I bet they don't, because they didn't know about it or didn't think of it. I know GPS is a slow repeating stream (the ephemeris repeats every 30 seconds and the almanac every 12.5 minutes) but that probably came before fountain codes.

Speculation about the past is probably unnecessary.

Reed-Solomon/erasure codes have been in operations since the 1960s

https://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_cor...

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#40

Post by krautsauer »

account42 wrote: post #11
krautsauer wrote: post #8

Earlier quoted context omitted.

That'd be a few 100 bytes at best… what firmware fits into that?

100 bytes in 20 seconds would only be 40 bps. Surely you can do better than that even using only one bit symbols (off/on).

With a flashing phone screen? 120Hz tops, right?
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