We all know that copyright law means you shouldn’t download copies of movies from shady torrent sites, and that you should pay for the music you listen to. We know it means people and companies have rights to stuff they make, like photos and music and books, and that there are legal and illegal ways of sharing those things.

But what most of us don’t really think about is how broad the net of copyright law really is.

Nominally, copyright protects content creators. If you write a book, or sing a song, or take a photograph, you have the right to control distribution of — to make money from — your original work. And, for a period of time, you are the only one with that right. If you take a picture, I can’t then print a copy and sell it for money without your explicit permission, because you have the right to the income from your own hard work. That much makes sense: legally and ethically, it’s yours.

That’s how it works in theory, anyway. Realistically, here in 2015, copyright law is a far cry from the original question of who has the right to copy a work. Now, copyright law is so much bigger.

The tendrils of copyright law reach worldwide into almost everything we consume, do, and are in the digital era. The rules and regulations about how the internet works, what privacy rights you have, and how the entire digital economy functions all spring from copyright. It’s everything from why a bar can’t buy a really big-screen TV to why you don’t actually own any of the media you pay for.

If you ever use a computer, or read, watch, look at, use, or listen to any piece of media or software created since printing or recording were invented, copyright law affects you.

Writer Cory Doctorow, probably best known for his work with tech and culture site Boing Boing, is a copyright expert. He’s joined a special project with the EFF to advocate for easing the burdens of DRM on consumers and content creators. And late last year he published a book, Information Doesn’t Want to Be Free, explaining the impact of copyright law on pretty much everyone in clear, plain English.

Doctorow’s book is a readable, concise look at the breadth and scope of copyright law in the modern age. Here are four key takeaways we should all keep in mind.

At this point, DRM and software go hand in hand. Everything comes with some kind of anti-sharing, anti-piracy, anti-copying, anti-any-unauthorized-use key built in.

The first digital battleground was music. After the Napster era dawned and crashed at the turn of the century, Apple’s iTunes and iPod launched an era of device-locked music. Now, the music industry has largely backed away from DRM (both iTunes and Amazon sell DRM-free tracks and albums), in favor of streaming services — but everything else is locked by platform.

But, Doctorow points out: all digital locks break. Every one can be broken, and is, usually quickly. From DRM on Kindle books to tech that supposedly locks down features on a blu-ray disc — any piece of code ends up with a cracked version all over the internet within, usually, minutes.

And that leads to…

The companies that make and sell digital locks want to know if you’re breaking theirs. They really want to know.

In one chapter of his book, Doctorow discusses the attempt of content-rights-owning companies to scrape YouTube to find, and have removed, any instance of their work. Any publicly listed video shows up, but videos flagged “private” do not.

Viacom sued Google over this, claiming that YouTube was complicit in every one of its users acts of copyright violation because it allowed videos to be marked as private. Viacom argued that they should have access to everything everyone puts on YouTube just in case any of it should be copyrighted material.

“Under Viacom’s legal theory — which was supported in amicus briefs filed by organizations representing all the major studios, broadcasters, publishers, and record labels — companies should allow the giant entertainment corporations to access all of our private files to make sure we’re not storing something copyrighted under cover,” Doctorow explains, then continues:

This is beyond dumb. It’s felony stupidity. It’s like requiring everyone to open up their kids’ birthday parties to enforcers from Warner Music, to ensure that no royalty-free performances of “Happy Birthday” are taking place. It’s like putting mandatory webcams into every big screen TV, to ensure they’re not being used to run a bootleg cinema. It’s like a law giving the big five publishers keys to every office in the land, to ensure that no one is photocopying books on the sly.

And the flip side of privacy is…

Everything is (or is becoming) a computer. Your phone, your tablet, your actual computer. Your car. Your television. Your printer. Your refrigerator, your lightbulbs, your washing machine. Your pacemaker. Your insulin pump. Traffic signs. Traffic lights. Airplanes.

The “smarter” and more network-connected everything gets, the more vital security is. It’s one thing if someone messes with a network-connected printer; it’s entirely another if they can remotely cut your brakes.

But privacy locks can weaken security, because “security” means different things to media companies and to consumers.

When digital locks get broken, the companies that install them want to be able to patch them, and keep them up to date, and make them temporarily not-broken again. But that means that companies want — and get — access to your stuff any time it connects to the internet, whether you want it to or not.

As Doctorow puts it: “Digital locks can’t work without renewability. You can’t ‘protect’ devices from their owners unless you can update them without their owners’ knowledge or consent.”

But then that makes the legal software as good as malware. “Renewability for digital locks means that you can’t be allowed to know what’s running on your computers,” he continues. “And that means you can’t decide what’s running on them. … The endgame for renewability must be that all computers are built with this facility in mind.”

“Imagine what it will mean when the person operating a car, or carrying around an implanted device, can’t know or control what’s running on that computer — but third parties can.”

Which means…

Doctorow draws two bright lines connecting copyright law to other major issues: government surveillance, as shared by Edward Snowden; censorship by private companies; and the necessity of free expression to civil and human rights.

Copyright claims are often used as a silencing tactic, where a party with power issues a takedown claim to get content from a party with less power removed from the internet.

For example, Doctorow cites copyright takedown notices issued by police departments demanding to have videos of their officers committing illegal acts taken down on the grounds that the police, not the person with an iPhone who recorded them, have copyright on the videos. Or takedown notices issued by the Church of Scientology to have removed articles from opponents who used leaked internal documents to criticize the organization.

“There are almost never penalties for abusing the takedown process,” Doctorow notes. “It’s the measure of first resort for rich and powerful people and companies who are threatened by online disclosures of corruption and misdeeds.”

Likewise, intermediary companies become gatekeepers of what end users may and may not consume — because they don’t want to get sued. So they fall into the “notice and takedown” scheme, and pass it all along to you. And that includes possibly having your entire broadband connection throttled or hijacked if a copyright holder doesn’t like what a user of that connection has been doing.

Because they have the right, and the ability, to keep an eye on you if you’re anywhere in the ecosystem: using a computer, phone, or internet connection that you didn’t build out of string yourself.

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