Finally real one way data transfer.
Show HN: ShadowCat – file transfer through QR Codes in a Browser
51–60 of 74 posts
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#52[dead]
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#53Earlier quoted context omitted.
I have a device with a camera and a touch-screen that only uses capacitive charging. I type a message. Bytes are encrypted. I hit send. QR codes flash on my screen. I use my PC or my normal phone to receive the encrypted bytes, and transmit them to you. You have the same device. You have your PC or phone flash encrypted QR codes. You use your device to receive, and then decrypt. Congratulations. You just invented IrD…
I specifically want this device to have no input or output hardware that could be used without my knowledge. IrDA could absolutely be used without my knowledge.
IrDA could absolutely be used without my knowledge.
Having actually used IrDA on Sony, Nokia, and Ericsson devices, no it couldn't.
In the real world, two IrDA devices have to be very specifically aligned, and also brought within just a few inches of each other. There's no way data transfer would happen without your knowledge.
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#54Earlier quoted context omitted.
I specifically want this device to have no input or output hardware that could be used without my knowledge. IrDA could absolutely be used without my knowledge.
IrDA could absolutely be used without my knowledge. Having actually used IrDA on Sony, Nokia, and Ericsson devices, no it couldn't. In the real world, two IrDA devices have to be very specifically aligned, and also brought within just a few inches of each other. There's no way data transfer would happen without your knowledge.
I blame the intentionally cheap receiving optics. Researchers have reconstructed a TV signal from a hotel room with closed blinds, by very accurately measuring the ambient light intensity of the room (as shown on the blinds.)
Knowing that, I doubt that someone with even moderate funding would have difficulty receiving a signal from any of the transmitters you mention.
But, in all honesty, if you put a physical cap on the transmitter and receiver, maybe I'm wrong.
But in the other hand, none of the devices I currently own have one of your transmitters, and they all have screens and cameras, so...
Thanks for the dialogue and for sharing your experiences.
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#55Single page file transfer using QR Codes and a browser. Sending device loads a file into the page, gets chunked. Receiver gets all the chunks through a camera, tosses lightly and reassembles, CRC to garnish. Designed to push data from an old phone that had broken comms after it took a swimming lesson in a coffee mug, it's been quite handy.
If the phone had broken comms, how did you get the code onto the phone to run?
Not OP, but I'm guessing by running the code on itself, i.e. turning the code into a QR code (or a series of them), then scanning those QR codes on the phone and reassembling them using a text-editing app on the phone.
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#56What's the length limit? I tried pasting some text and got this message: code length overflow. (85700>18672)
QR code has limits, use the file transfer to chunk it. :)
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#57Cool stuff. I’m fond of the “single HTML file” deployment option.
Cheers!
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#58Single page file transfer using QR Codes and a browser. Sending device loads a file into the page, gets chunked. Receiver gets all the chunks through a camera, tosses lightly and reassembles, CRC to garnish. Designed to push data from an old phone that had broken comms after it took a swimming lesson in a coffee mug, it's been quite handy.
If the phone had broken comms, how did you get the code onto the phone to run?
With great difficulty...
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#59This is cool and minimalistic! I've been noodling on https://qr-send.com which is a slightly more polished version of the "erasure fountain codes + stream of QRs"-idea, inspired by divan's Txqr posts but using Wirehair FEC for the fountain code (basically: you receive ~file size bytes via QR codes and it magically assembles them into the source file regardless of missed codes). It's an offline-first progressive web a…
What is the fastest you can transfer data from ~10 meters away using a modern phone front camera and screen? Surely 100 kB/s is slow?
Re: Show HN: ShadowCat – file transfer through QR Codes in a Browser
#60Single page file transfer using QR Codes and a browser. Sending device loads a file into the page, gets chunked. Receiver gets all the chunks through a camera, tosses lightly and reassembles, CRC to garnish. Designed to push data from an old phone that had broken comms after it took a swimming lesson in a coffee mug, it's been quite handy.
This is wild. I made an identical program 24 hours ago. Mine just transfers text files