Supposed you are able to randomize your string (which is fairly simple to do), how do you revert it back to the original string at the server to make any meaning out of the randomized data? And now supposed that you are able to come up with an algorithm to un-randomize a randomized string, isn't it just like re-inventing the wheel (in the sense of data encryption). If you don't really care about unrandomizing the string, you can just simply create a random string at the server side because it doesn't matter what the uploaded string is, it still has no particular meaning so why not just create one on the server and save the bandwidth?