Can I make an app to remove DRM(Digital rights management) tag from a video in iOS?

Question

I am making an app to remove DRM tag from videos downloaded from the internet. Can i do that? If yes how?

Answer 1

Not really. DRM is for protection of the content usage. In reality the principle of DRM is very simple:

• Media content is encrypted
• To decrypt media content you need a key
• To get a key you need a license
• License is obtained from the license server of the content provider which checks that you have rights to play the content (eg. you have valid subscription or you purchased or rented the content)
• This all happens in DRM component on the device which is designed to be kind of secure while still running in untrusted environment (client device). That usually includes some hardware integration of DRM component ensuring that your application will never get access to keys or decrypted content.
• HW integration is usually provided when both HW and DRM component come from the same company. Third party manufactures can implement selected DRM component on their HW - that is usual for Smart TVs, set-top boxes, etc.

Now it pretty much depends on what content you want to "crack". If you want to remove DRM from third party content you can't do much - especially if HW integration is used. With just SW DRM component it can be still unbelievable complex because again - that SW was most probably written to make reverse engineering extremely complex task - a lot of obfuscation, runtime checks for debugger, etc.

If you own both server and client side you should simply provide content without DRM in the first place and don't try to remove it afterwards.

There is another problem - using such app on third party content would be violation of usage rights and depending on what would the next step be, it could be even illegal in some countries.

If you are just trying to get DRM-free content of what you've purchased, it is not worth the effort to even try it.