Consider that a sufficiently talented programmer constructing a very powerful piece of malware could, in fact, alter every copy of something everywhere, simulta

Consider that a sufficiently talented programmer constructing a very powerful piece of malware could, in fact, alter every copy of something everywhere, simultaneously, no matter what it's format. And they wouldn't have to be 100% successful, they'd only need to affect enough copies to sow doubt into people minds about which is the authentic copy. My point applies to all digital media, for the simple reason that computers are remarkable in their ability to modify the state of very small things.