The illegal number: Why the possession of this prime number could get you arrested in the US

Illegal prime number YouTube/Wendoverproductions

There’s an illegal number that could get people arrested in the US if they wrote it down or distributed it. How a 1,400 plus-digit prime number became illegal is a bit complicated, but it has something to do with copyrights under the Digital Millennium Copyright Act.

YouTube channel Wendoverproductions stumbled upon an entry in Wikipedia that explains how a prime number became illegal, at least in the US where it is under the DMCA. It may sound unbelievable, but apparently it is a real illegal number to possess.

“Just the possession of this number is enough to get you arrested in the US,” the video warned, posting a jumbled version of the illegal prime to avoid breaking the law.

As the video explained, encrypted websites, like an online banking site, send out a public key number to the bank’s server. The bank will then check if the two prime numbers it possesses matches the public key number when multiplied together. If so, the user will be let in.

Everyone can take possession of the public key, but only the bank has the private keys. To know the two private keys, one needs a computer that can factor the private keys, and even with one it would take a very long time. That’s why it’s difficult, almost impossible, to log into an account without knowing the private keys, which have thousands of digits each.

“The bigger the prime number, the longer it takes to factor and the more secure it is,” the video explained, adding there are organisations that are willing to pay hundreds of thousands of dollars for those who can discover a new prime number that have at least millions – even billions – of digits.

So what has this math got to do with a number being illegal to possess?

As the video continued, when the DMCA was passed in the US in 1998, circumventing copyright measures or distributing tools that could be used to get around copyright became illegal.

The illegal prime, which starts in 8565078, is the source code that is used to encrypt the copyright protection of DVDs. It stops people from downloading or duplicating films on their own. If the number is distributed or made known to the public, they would be able to copy movies, rendering the protection useless.

So anyone who copies the prime number is basically distributing tools that could be used to circumvent copyright measures, which is illegal under the DMCA.

And that is why it’s illegal to possess this prime number, at least in the US.

Watch the video for a detailed explanation: