So, my actual motivation is solving a specific problem I set myself: if I have two or more processes running on different machines, with access to the public internet, but no guarantee of locally open ports beyond 80 and 443, no knowledge of any existing sibling processes, and no guarantee that any previously-established communication channel (like a mail server, message queue or coordinating service) is still active, how do they form a peer group?

The first not-completely-terrible solution I hit upon was for them to monitor existing chatter-heavy online se... (read more)

It seems like other people have built solutions that use steganography with the image pixels themselves, given that I see examples on Wikipedia.

I can't be remotely useful with the text stuff, though, my coding skills are such that I still have trouble generating token frequency histograms from text files and my most persuasive "chatbot" relayed an entirely pregenerated script to the user, only took 1 bit of user input, and was written on a graphing calculator. (I still got my Theory of Knowledge to feel empathy for it and be unwilling to let me d... (read more)

3philh5yIf cyphertext in image metadata would be acceptably well-hidden, this should be as well: you can hide four bits per pixel using the least significant bits of the RGBA channels. A human won't be able to tell the difference between #FE007BFE and #FF017AFF. (This assumes .png. I don't think it would work very well, if at all, for either jpeg or gif.)

Open thread, Apr. 01 - Apr. 05, 2015

by MrMind 1 min read31st Mar 2015180 comments


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