This is the question / thought experiment that the Owner-Free File System explored[0] (based on the XOR operation), and the legal / philosophical issues are dis

This is the question / thought experiment that the Owner-Free File System explored[0] (based on the XOR operation), and the legal / philosophical issues are discussed in the famous essay "What Colour are your bits?".[1] An idea that is often missed in these discussions is that if you have two random-looking files which, when XORed together, produce an interesting file, it isn't clear which of the two source files were created by someone with access to the interesting file. For example, if you produce a sufficiently large random file, I can create another file which, when XORed with your file, implicates you in copyright infringement. My non-expert conclusion is that unless a third party can prove which file was created first, there is no way of knowing who to prosecute, like having an eye witness trying to separate identical twins (which I believe has been a problem in court cases before). There is, however, the counter-argument that merely publishing large random-looking data files is evidence of a conspiracy to aid copyright infringement, although the same could be said of running a Tor node. [0] https://en.wikipedia.org/wiki/OFFSystem https://en.wikipedia.org/wiki/OFFSystem [1] https://ansuz.sooke.bc.ca/entry/23 https://ansuz.sooke.bc.ca/entry/23