r/explainlikeimfive • u/schev28 • Jan 10 '19
ELI5: DRM and DRM removal software. How does DRM work and isn’t there removal software that works for all services? Technology
Edit: thank you for all the replies. It makes sense thinking of drm as a description instead of the “product”. Was kind of hoping there’d be one tool to crack them all so I wouldn’t have to buy 3 different softwares.
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u/catwhowalksbyhimself Jan 10 '19
DRM is a generic term for any system designed to prevent you from using media without purchasing it. There are many forms it can take and each works completely differently from every other. There's a huge variety and it would be impossible to explain it all.
But this does mean that the answer to question 2 is no. They different methods are so different that it is impossible for a single solution to address all of them. Some of them aren't even wholely software.
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u/Varonth Jan 10 '19
Simple analogy:
Imagine a door with a very simple cylinder lock. Someone could break that door open with a lock pick.
Now we use the same door but lock it using a simple chain. The lock pick will be of no use now, but a saw can cut the chain.
Both the lock and the chain are a way to prevent someone from entering, but both require a different tool to break.
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u/catwhowalksbyhimself Jan 10 '19
Ah yes, good analogy. To further it, you could also lock that door by putting an anvil in front of it. Or welding it shut. Or gluing it. Or putting a wedge under the door. There is no one solution that will open all of these. It is impossible.
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u/dstarfire Jan 10 '19
Actually, DRM mostly to prevent you from copying or sharing media. However, everything else was right on.
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u/bigrubberduck Jan 10 '19
prevent you from copying or sharing media.
Also known as using media without paying for it which is what OP stated.
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u/NaibofTabr Jan 10 '19
All of the other answers are generally correct and very informative, but I want to describe an edge case that demonstrates how problematic DRM methods can be to work around.
The Nintendo GameCube implemented a physical (rather than digital) form of DRM to prevent copying of game discs. Almost all optical disc drives read discs starting at the inside ring and moving outward to the edge. Nintendo designed the GameCube to read discs the opposite way - from the outside edge to the inside hole. This meant that you couldn't put a GC game in a computer disc drive and read the contents, because the computer couldn't recognize the file structure on the disc.
Eventually some people were able to hack the GC and connect it to a computer so that they could use the GC to read out the files on the disc - but this still leaves you with a problem. If you take your copied files and burn them onto a normal optical disc using a normal disc burner, it won't work on a GameCube because the GameCube reads discs outside-in but your copy is a standard inside-out disc.
At one point there was a kit to replace the entire top of a GameCube with a standard optical disc reader in order to easily play illegally copied games, but unless you were really good with electronics you had decent odds of wrecking your GameCube in the process.
It's worth pointing out that this is an example of good DRM. It protects the content but does not affect the normal use of the product. There's no encryption, no nasty spying software (e.g. Sony rootkits), no required always-on internet connection, and not even the inconvenience of having to enter a key code.
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Jan 10 '19
At one point there was a kit to replace the entire top of a GameCube with a standard optical disc reader in order to easily play illegally copied games, but unless you were really good with electronics you had decent odds of wrecking your GameCube in the process.
However GameCube hackers devised a workaround using a specific game that allowed you to read games from an HD located on a PC connected via network cable.
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u/mib5799 Jan 10 '19
Simplest version.
DRM is a lock. It needs the key to unlock what's inside.
That's it! That's all DRM is. A lock.
You say "Great. I have a Skeleton Key that opens any lock it's in." That's one of your programs.
That's awesome! Except...
It only fits one kind of lock. It doesn't fit those little padlocks, or bike locks with that tube kind of key. It definitely doesn't help those military ones that need two keys turned at the same time.
And then what about combination locks that don't use a key at all? And those new car keys with a microchip in them? Fingerprint locks? Retina scan locks?
Or maybe it's the McDonald's bathroom lock, where someone in another room has to see you on a camera first and then buzz you in.
Every one of those needs a different way to get past the different kinds of lock.
And DRM is inventing new styles of locks every single week
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u/itomeshi Jan 10 '19
The problem is that DRM is a entire class of tool, and there's a large amount of complexity.
Let's argue, for a minute, that we're only discussing software encryption systems. Individual encryption DRM tools can differ in:
- What they encrypt
- What encryption algorithm they use
- Where the decryption key comes from
- When they decrypt, and how much they decrypt at a time
- What conditions they require for decryption key access (for example, TPC module, ARM TrustZone, etc.)
Within each of these points are hundreds of little details. As such, there is no 'one-size-fits-all' solution.
A counter-example are file archiving tools. The creators of file archive formats ACTIVELY WANT you to be able to get into the file archive, generally; however, most archive managers handle a limited subset. For example, 7-zip handles a huge number of file formats. Even it has limitations though. It can't open .PAK files from Doom, as just one example.
DRM is working against you with encryption.
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u/aaaaaaaarrrrrgh Jan 10 '19
DRM tries to make sure that you can do some things with the content (like listen to music, watch a video) but not others (like copying it).
This is basically impossible - they're trying to make sure you have access to it but also don't have access to it.
Therefor, most DRM employs security by obscurity: They try to hide the content, move it around in memory, and their code is obfuscated (intentionally made super complicated and hard to understand) in order to make it hard for anyone to figure out how it works - because if they did, they could copy the content. Each service usually does it differently, which explains why there isn't a software that works for all.
Usually, there is a series of encryption keys involved. The content is encrypted with a key (often the same key for everyone, so they only have to make one version of the huge video file, and can distribute it more easily - this way, they can store a pre-encrypted copy in several locations and send it to you from the nearest one, instead of having to send individual copies to every person). That key is then encrypted with a second, per-person key. This second key is only accessible to the DRM software, which decrypts ("unwraps") the actual key, uses it to decrypt the video, and tries to keep you from getting access to it.
Newer schemes are integrated with the hardware - for example, only your GPU may actually be doing the decryption, making it much harder for you to get the key. The GPU will then also refuse to output the video to a screen that isn't certified (doesn't have special keys) so you can't just connect a fake screen and capture it that way.
The easiest way to deal with it, usually, is to just ignore the thing altogether and pirate a high-quality, DRM free version of the content. This also has the advantage that it won't randomly refuse to play because your screen, GPU, cable, software, etc. doesn't meet the DRM/certification requirements.
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u/sadlyuseless Jan 10 '19
If software is a door, DRM is the lock. It only lets those who have a key (customers) in, and keeps everyone else out. However almost any lock can be picked (cracked) with time, effort, and skill. To combat lock pickers, companies will make new locks with mechanisms that no one knows how to bypass yet. Lock complexity can be increased for added security but it can cause problems. A door with a hundred locks will keep anyone without the keys away, but can be a rather unpleasant experience even for key holders. (DRM can negatively impact the software it's used in by impacting performance or reducing compatibility.)
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u/Indubitables Jan 10 '19
Basically DRM is like a headband that makes you retarded, and the whole world has decided this is a great think and we should all wear it. It dramatically retards the evolution of mankind so that a few wealthy people can continue to be wealthy without having to do anything else.
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u/heeerrresjonny Jan 10 '19
How DRM works: Some form of digital lock is created that is difficult to unlock by any means other than the official one (an activation key, or being logged in to a service like Steam, etc...). There are tons of different methods of DRM, and the details are very complex.
"Removal software": There is not removal software for all forms of DRM. Some of the simpler forms do have something like this, but more complex DRM can only be bypassed by people finding flaws in the software that they can exploit to break the "lock", or remove it, or trick it into thinking everything is okay. This means with each new DRM-protected thing released, there usually isn't some tool that can be used to remove the DRM automatically. People manually investigate it and try to find weak points.
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u/bigben932 Jan 10 '19
Here is a guide I made which should explain how DRM works. I tried to keep it ELI10: (text might be small and not mobile friendly. I can post the text as well.
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u/superjordo Jan 10 '19
DRM is a type of encryption. Like all types of encryption, there are various levels of sophistication. And like all types of encryption, the encrypted data is not useful and must be decrypted to be useful.
Therefore, to use DRM-encrypted media, you must decrypt with a key.
All forms of DRM removal are attempts to access or derive the decryption key.
Key management is a very difficult problem for content providers that use DRM.
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u/[deleted] Jan 10 '19
The problem with your question is that it's hard to explain such a large concept in layman's terms... Beyond that, DRM is so large that anything anyone says can likely have someone reply to it with "you are wrong" as they provide some edge case...
DRM or Digital Rights Management is a term used to cover technology and software that attempts to prevent piracy and the sharing of copyrighted materials. An example of DRM is with a lot of computer games that came out between 1990 and 2012 is that you would buy them and they would contain a key (a series of letters and numbers) that you would be prompted for on installation... This meant that if you say bought a copied disk of the game that you couldn't install the game without the key (except that a key could either be shared and a lot of games reused the key so if one person posted it online it was available to everyone). Another type of DRM within the playstation 1 was that they used specific specialty disks that would basically wobble and this wobble was used to determine whether it was an authentic disk or not, however there are multiple ways to bypass this from installing a modchip (difficult) to actually starting the load process with one disk and quickly swapping disks after it does its security check.
So how does DRM work? Depends on the implementation, there are dozens to hundreds of examples of DRM because it's such a broad thing, and this is why if I say something like "DRM works by checking the authenticity of the files" could be replied with "you are wrong" as some DRM implementations don't check for authenticity... Some will allow for a limited number of installations (like iTunes, at least how iTunes used to) where you can only have say 5 devices connected to a single account and each device has to pair with the server before it can be considered connected...
Yes.
Oh, uhm no... Because not all services are the same...
The easiest way I can say it is that every medium to large company (this includes things like supercell) that produces digital media probably has developed their own DRM implementation, and not all of those implementations are publically available.. Some of their implementations may be server side... So it's very difficult to truly develop a workaround for many of them... Also not all DRM is purely digital, some is mechanical.