Fun I had a similar idea on April this year, I thought about using streaming png's (nodejs) as information source, first I was thinking about using some qr-code

Fun I had a similar idea on April this year, I thought about using streaming png's (nodejs) as information source, first I was thinking about using some qr-code technique to make transmissions secure. Then I thought, I could use something better like qr-code multiplication inside of a png stream that looks like a video with some qr-codes that flash from time to time. A smart-phone application would make the data readable again (decryption). You would need to whisper a secret key personally into your friends ear, so he can enter the sequence into his smartphone app. All-in-all it was a concept to use png's like videos with "cut-scenes" a-like qr-code's that get multiplied and cross-checksummed afterwards. Might sound stupid, but think about it. I wasn't approaching to solve your post-apocalyptic scenario, but to make something speedier+secure than wifi/bluetooth/infrared. What do you think? A friend who's exceptional at maths (I'm not) told me it's not possible, however I don't like when naysayers come and tell it's impossible. Still it demotivated me. Do you think it's possible? Explained in two words: "Optical Transmission"