#visual encryption

Hey, this sounds like a dry subject, doesn't it? All boring and stuff, right? Well, I suppose I'm not here to disappoint. A few days ago, I suddenly had the urge to do something entirely random, and thus a digital encryption algorithm was born.

...What, I haven't lost you yet? Can't help but wonder what kept you. Most people would stop at the word "algorithm", or even before. Anyway, I feel I should demonstrate it. Let's take a look, maybe?

Augh! What is that? Is that...it is. It's a map from RPG Maker XP. I'm embarrassed I still have this picture. I don't want to get rid of it, but at the same time, I don't want it simply there on my hard drive. Luckily, I have this fancy new encryption algorithm I set up for images. Let's see what this sucker can do.

There. Can't tell what it is, at all. Now, if you're wondering about how easy it is to reassemble back into the original, the answer is that it's pretty easy, assuming you have the key. Unfortunately, you don't. That key consists of 19 different numbers of varying sizes. Want me to do the math to see how hard it is to randomly guess the key? Sure, why not?

640 * 640 * 640 * 480 * 480 * 480 * 100 * 100 * 100 * 100 * 100 * 100 * 640 * 640 * 640 * 480 * 480 * 480 * 65536 = 55,081,682,656,191,541,772,550,144,000,000,000,000,000,000,000,000

Oh, hey. I don't think I've seen something with that many digits before. What would that number even be called? Well, apparently that is about 55 quindecillion. My dictionary doesn't even believe it's a real word yet. For reference, one quindecillion is 10^48, meaning that your odds of randomly guessing the key are pretty staggeringly low. What, you think you can automate it? You'd better have a person on standby 24/7, because I doubt anyone can afford enough hard drives to try every combination.

Huh, you say that's not good enough yet? I have to do better? Well...I suppose there's more I could do. For one, what happens if I add the option to make it go over the image multiple times in a row?

It doesn't look that different, does it? To be fair, it isn't that different visually. But, it took a lot longer to apply the filter, and it would take a lot longer than that to reconstruct it. On top of that, we just multiplied those odds by another 65536. For simplicity, I'm combining like terms into exponents:

640^6 * 480^6 * 100^6 * 65536^2 = 3,609,833,154,556,168,881,605,846,237,184,000,000,000,000,000,000,000,000

Cool, another number I haven't seen before. This one is 3 septendecillion, which is starting to sound a bit childish. That is 3*10^55, for reference. Those odds are fifty-five digits of "ain't gonna happen" to anyone who wants to know why the heck you have this image.

Wait, what? Is that still not enough for you? All right, fine. There's a bit more I can do, I suppose. I only included maximums for several values, but they can actually go below zero too. Let's do that. I would like to note that at this point, I'm going to stop throwing images at you. They won't change much, aside from the specific locations of static. Anyway, here are the odds:

1279^3 * 959^3 * 640^6 * 480^6 * 100^6 * 65536^2 = 6,661,232,378,135,545,546,446,945,731,269,391,344,313,516,949,504,000,000,000,000,000,000,000,000

All right, so according to Wolframalpha, your odds of guessing my key at this point are about 1 in 6.6 trevigintillion. This is definitely sounding childish now. We're currently at 73 digits of "screw you" to whoever wants to know what the heck that screen of static was. And all this while imposing reasonable limits on the numbers you can use in the key.

Oh, what? You don't want reasonable limits on the numbers? All right then, suit yourself. Let's uncap everything that isn't a percentage:

65536^20 * 100^6 = ?

All right guys, time for the bad news. Wolframalpha has stopped being helpful until I pay premium, presumably because they're afraid of the terribly large numbers I'm having them calculate. They won't even tell me the name of this one, just that it's 109 digits long. Wait, 109? Guys, your odds of breaking the encryption at this point are actually less than one in one googol. That's 109 digits of "Are you solving this with an infinite improbability drive?" in the face of whoever looks at your images. For another comparison, that number is bigger than the estimated number of  atoms in the observable universe.

All right, screw it, we've calculated the odds this far, how much farther can we go? The answer isn't simple. I can reprogram this whole thing in a language that doesn't support numeric caps, easily. At that point, the encryption becomes a combination of how much you're willing to pay for hardware and how long you're willing to wait. It also technically lowers the odds of successfully decrypting the image (without the key) to a lowly one in infinity. Only technically, though. There are much more reasonable limits that can be applied by anyone planning to break your files, because who wants to sit there for a week waiting for their photo to load?