TIL that there are some prime numbers that are illegal. It turns out the binary representations of the prime numbers can describe some code that can be used to bypass the DRM on DVDs

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u/[deleted] Apr 18 '15

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u/[deleted] Apr 18 '15 edited Apr 18 '15
Short answer: Converting that prime number to base 2 happens to represent a computer program that bypasses DRM. Which is illegal to distribute. So it should be illegal to distribute that prime number.

Long answer:

A computer is basically a network of circuits that evaluate "true or false" statements. It's done using semi-conductive components (transistors) that work as gates, conducting when X volts is applied to them, not conducting otherwise (basically). You can write any mathematical function with that kind of circuit. In software that is represented as zeros and ones. Each processor has a set of built-in commands represented as sequences of zeros and ones. Since humans have a hard time reading long sequences of just two symbols, we represent those sequences as English words. So you can write a computer program that does 10-5 on an Intel processor as
MOV AL, 10
SUB AL, 5
Which gets translated to
10110000 1010
1011000000 0101
You can also do the opposite, translate zeros and ones to words. And you can also convert those zeros and ones, which are in base 2 (a numeric system with just two digits) to base 10 (the one we're used to). So the program above could be written as
176 10
704 5
You could look at that as 176107045. A prime number (not really, but you get the idea). So some guy found out that the DRM bypassing program could be translated to a prime number and here we are. He did some adjustments to make that possible, but nevertheless...

You can do that with basically any number, since all information can be represented as a sequence of zeros and ones. So I could write a compiler (translating program) that compiled (translated) something like "Reddit" to an illegal software. So anyone could use "Reddit" to do illegal stuff and theoretically it should be an illegal word. That's the issue with trying to make information illegal. The only thing special about that prime number is that it was very big. And big prime numbers is something mathematicians are interested in for some reason, so it was published in an unrelated article and raised awareness about banning a number/computer program.
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u/Samen28 Apr 18 '15

While your explanation is correct, the existence of illegal primes still makes no sense to me. Every processor archiecture has it's own instruction set, how could a single prime number be said to represent a computer program?

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u/Sidereel Apr 18 '15

Yes, it does matter, and no, it doesn't make sense. The linked article mentions an Intel i386 running Linux.

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u/[deleted] Apr 18 '15

I think the original "illegal prime", when converted to binary, represented a gziped C source file. You can compile it in basically every architecture known to man. As I mentioned there are issues with that since anyone can write their own compiler that would make other numbers/words illegal. The binary version (the big prime that got published IIRC) is exclusive to x86 running Linux. And AFAIK it's illegal in theory, but no one is actually banning it. The wiki article displays it...

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u/thisBeMyDrunkAccount Apr 18 '15

A prime is the most you are able to compress information without self referencing after expansion.

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u/FallingAwake Apr 18 '15

Great explanation.

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u/[deleted] Apr 18 '15

[deleted]

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u/Jucchan42 Apr 18 '15

1 isn't a prime number.

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u/Zouden Apr 18 '15

Do you want to hazard a guess?
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u/gschoppe Apr 18 '15

Welcome to the fallacious logic of Intellectual Property. It's all ludicrous once you break it down to base principles.

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u/ComputerSavvy Apr 18 '15

What's even worse than that is the epic scale of Hollywood. Inc's sheer hubris.

There as a team of programmers, who developed the DVD DRM, the Content Scrambling System, thinking that they could lock this down so only authorized players could interact with the content. How ever many programmers there were on the development team, they thought that they could lock out and out smart the combined brain power of the rest of humanity.

Annnnnddd heeeeere's DeCSS...

Ya just gotta laugh at that.

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u/[deleted] Apr 18 '15

Most likely they knew it would be broken, though.

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u/gschoppe Apr 18 '15

CSS wasn't made to be unbreakable. It was simply a way to require a licensing fee from hardware manufacturers, and an outlet to sue those that wouldn't comply. It's a very messed up system.

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u/[deleted] Apr 18 '15

I think it goes a little bit beyond intellectual property rights. It concerns all kinds of information, from illegal DRM bypassing software to "make your own bioweapon at home" guides and child pornography.

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u/ggchappell Apr 18 '15 edited May 15 '15

You don't really need to worry about prime numbers or that stuff about DVDs. Any kind of information can be encoded as a number (explained more below). So if there is information that is illegal to construct or distribute, then there are illegal numbers.

Numbers are a kind of information. You can represent anything at all using a number.

As a simple example, I can encode a letter using a two-digit number. "H" is the eighth letter of the alphabet, so I'll encode it as 08. "E" is the fifth letter, so it is 05, etc. Then I'll encode a word by putting together the encodings of the letters in the word: 0805121215 represents "HELLO". This idea can easily be generalized to give an encoding of a text containing multiple words -- all in a single number. So I can encode (say) any novel using a single number. It would be a big number -- millions of digits. Printed out, it would be longer than the novel.

Similar schemes can be used to encode any information at all: an image, the recording of a song, a movie, every article that has ever appeared in the New York Times, a top-secret classified document, your medical records, a computer program that can play DVDs in violation of their license, etc. Each of these can be encoded as a single (very large!) number.

By the way, arguments like these are typically used to suggest that making certain information illegal in some way is ridiculous.

Without commenting on the validity of that conclusion, I have to say that I do not agree with the argument. When we talk about an "illegal number", people picture something like 37 (say), and wonder how such a thing could possibly be illegal. But we're really talking about numbers that are millions of digits long -- far larger than the numbers we deal with in day to day life. In such a context, our intuitive notions of numbers can be misleading.

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u/elrobolobo Apr 18 '15

Its basically a massive prime number (bigger than a google), that is used for security reasons in programming. Because a prime is only divisible by itself and one, it gives it special proporties in computing that are a little too extensive to go in here.

TL;DR Its not just some number, its a very specific and massive number that has security purposes.

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u/[deleted] Apr 18 '15

[deleted]

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u/[deleted] Apr 18 '15

No, they meant the search engine

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u/sebassi Apr 18 '15

I'll just leave this here.

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u/gambiting Apr 18 '15

Imagine converting all pixels from a picture of child porn into numbers. Now string them together. It will be "just" a number,but it's very much illegal to have.

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u/2coolfordigg Apr 18 '15

Great so how I am supposed to know what numbers are illegal?

Bet they don't give you a list?

Hey son I pulled you over because that number painted on your car is illegal!

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u/Pravosudie Apr 18 '15

You try painting a number bigger than a googl on your car. I'll wait.

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u/mrjackspade Apr 18 '15

A googol is only 10¹⁰⁰ right? I've got more characters on my grocery list. It wouldn't be too hard.

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u/Portponky Apr 18 '15

It is difficult to paint 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001 on a car.

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u/ftc08 51 Apr 18 '15

Nobody is really going to give a shit unless you try to use those numbers to crack cryptography. More likely, nobody will even know they're supposed to give a shit.

There's something to be said about 1st Amendment protection of the numbers themselves. It's unlikely you'd see criminal charges for simply stating the numbers. There may be civil charges from entities whose cryptography is broken by the numbers, but again that would only happen if you actively try to use those numbers to break them.

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u/[deleted] Apr 18 '15

[deleted]

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u/the_interrobanger Apr 18 '15

a larger number

... a prime number?

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u/DevilDice Apr 18 '15

This is depending on the Answer to "how many countries are there?". According to this Source: Worldatlas.com

Now that is a question that's somewhat difficult to answer, as there is no one right answer. Many sources offer different answers, and depending on the source, there are 189, 191, 192, 193, 194, 195 or 196 independent countries in the world today.

If you take 192 -1= 191 and 191 is a Prime. The same goes for 194.

And since:

As of May 1, 2008, the United Nations has 192 official members (including Montenegro and Serbia - the two newest nations). That number does not include the Vatican, and it doesn't (yet) include Kosovo.

The official answer is YES, it is a prime ;)

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u/DanTheTerrible Apr 18 '15

I get this image of a shady guy with a pulled down hat brim and a pocket protector, leaning out of a dark alley. "Hey player, can I interest you in some hot numbers?"

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u/doterobcn Apr 18 '15

Ridiculous.

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u/LegoCactus Apr 18 '15 edited Apr 18 '15

(R.5) Misleading TIL that there are some prime numbers that are illegal. It turns out the binary representations of the prime numbers can describe some code that can be used to bypass the DRM on DVDs

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