You don’t have to be a cryptographer to understand this stuff, but you do need to have a conceptual grasp of the way that scrambling and descrambling work. Fundamentally, this is about four things. First, there’s the unscrambled file, called the “cleartext,” which would be the movie you watch, the song you hear, or the book you read. Next, there’s an “algorithm”—a mathematical system for scrambling the text. These algorithms are usually public and well understood, because no one is ever sure if an algorithm is secure until all her peers get a chance to look at it and check it over for flaws. Third, there’s the “key,” a secret password that’s fed to the algorithm along with the cleartext in order to produce the scrambled file. This scrambled file (our fourth thing) is called the “ciphertext,” and in that state it’s an indecipherable mess of no value to anyone unless they have the key to descramble it. People can copy this encrypted file all they want, and it won’t ever substitute for the legit product, because it’s indistinguishable from random noise. If the algorithm works, the file can’t be unscrambled unless you have that key.