How can one read a file or change a file bits without reading the entire file. But first of all how can I read a file in such a way that I get it's bits. I want to read MP3 file and change it bits but I don't want to change the information stored on it like artist name, album year, but want to read it and change bits in such a way that MP3 players won't recognize this file as MP3, and most importantly how to change the file back to original bits. Some one also mentioned XOR to me which is also reversable as he said but XOR was out of my understanding, I mean I know this from Gate (OR gate, NOR gate,etc) but I couldn't figure how could I apply it to my problem, case.
I'm really stuck on this problem.