My favorite class of error correcting codes is one I haven't seen mentioned here: rateless / "fountain" codes. https://en.wikipedia.org/wiki/Fountain_code htt

My favorite class of error correcting codes is one I haven't seen mentioned here: rateless / "fountain" codes. https://en.wikipedia.org/wiki/Fountain_code https://en.wikipedia.org/wiki/Fountain_code You take any message and can generate any amount of coding symbols from the message, and a receiver that gathers _any_ K of those coding symbols can decode the message. The mental image I have is using these to send messages into space -- a receiver could pick up at any point and just wait until they have any K coding symbols and they'll be able to decode the message. My understanding of all this stuff comes from USENET and par/par2/yenc (where, IIRC, the message gets packaged up in plaintext blocks and if your local server is missing N blocks you have to collect N parity blocks and you can recover from there, but my recollection is probably fuzzy), and I imagine rateless codes would be quite useful for USENET binaries.