TWL #7: This Number is Illegal | Wendover Productions

0:00So, there's this fantastic Wikipedia list, descriptively titled Wikipedia colon unusual articles. I just remember it as that Wikipedia list. It's a collection of hundreds of articles about unusual, unexpected, and unbelievable subjects. No matter what link you click, it's bound to be interesting. For that reason, every week I'm going to click on a new link and teach you a little bit more about our amazing world. This number is illegal. Well, kinda. I switched out a few digits to protect myself since, you know, it's illegal, but just the possession of this number is enough to get you arrested in the US. To understand why, we need to learn some cryptology. Prime numbers are numbers that can only be divided by themselves and one. For example, nothing multiplies together to get 7 other than 7 and one. Nothing multiplies together to get 29 other than 29 and one. This will be the same for all primes. It's not that hard to check if a smaller number is prime. For 7, you just check if 7 divided by 1 is a whole number, 7 divided by 2, 3, 4, 5,

1:046, nothing other than 7 can divide 7 into a whole number. As you get to bigger and bigger numbers, you have to check more and more times to determine if a number is prime. That means that it's exceedingly difficult to find new primes. The largest prime number that we know of right now is 2 to the power of 74 million, 2700, 281, minus 1. There's an infinite number of primes since there's an infinite number of numbers, but it just takes an enormous amount of computing power to find these primes. So what's the point of finding primes? Well they're actually quite useful for encryption. For the sake of simplicity, let's take two small primes, 11 and 13. If we were actually encrypting data, we would be using primes with thousands of digits, but that would probably make this explanation a little complicated. Now multiply 11 and 13 together in your head. You can probably figure out pretty easily that together they make 143. Now how long would it take you to work backwards and figure out what multiplies together to

2:06get 143? Probably a pretty long time. It's the same with computers. It's very easy for them to multiply two numbers together and find out what the product is, but it's very hard for them to take the product and find out what the factors are. When you're logging on to say your bank account online, the computer will send the number 143, which is known as the public key to the bank server. If the bank will then check if 11 and 13, the private keys, multiply to 143, and if so, it will let you in. Everyone has the public key, but only the bank has the private keys. If you wanted to find the private keys, you would need a computer to factor the public key, which would take thousands of years, because once again, in the real world, the keys are in 11 and 13, their prime numbers with thousands upon thousands of digits. With the amount of money that it would take to set up a computer system that could actually factor the primes, it's just not worth it. The bigger the prime number, the longer it takes to factor, and the more secure it is. That's why organizations like the Electronic Frontier Foundation are willing to pay up

3:10to $250,000 for new prime numbers. Alright, that's all the math we're going to do today, I promise. Back to our legal number. In 1998, the Digital Millennium Copyright Act was passed in the US, making it illegal to circumvent copyright measures and to produce or distribute tools that could be used to get around copyright systems. Our legal number, 8565078, and so on and so forth, is a prime number that is the source code used to decrypt the copyright protection of DVDs. The copyright protection was used to stop people from downloading or duplicating movies on their computers, and with this number, the protection was rendered useless. Programs were created that allowed individuals to make bootleg copies of movies all because of this number. All the while, individuals were breaking the law not only by copying DVDs, but also just by being in possession of this number, an easily findable prime. I hope you enjoyed this week's episode. Last week I covered Big Mac economics, which you can find here.

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