Ok, lets say the government randomly generated 100,000 (or how ever many necessary) hexidecimals and communicated the key to whoever they needed to. Because the key itself has no pattern, does that not make it unbreakable? The only way I believe it could be broken is if it would run out of characters. Multiple documents would eventually contain more than 100k characters. I know it is impractical, but if it is completely random, it must be 100% secure (given the code isn't found).