system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why Blu-ray Encryption can be cracked, but not AES-256 bit Encryption?

I don't understand how content companies trying to encrypt media on Blu-ray discs, and in the past trying to encrypt HD-DVD, have failed.  Why can't they just use AES- 256 bit encryption which websites use to protect your data.  That method has yet to be cracked and can't be impossible to implement on physical media.

All help is greatly appreciated.
gpt
The problem isn't the quality of encryption, but that they have to distribute decryption keys to anyone that wants to actually watch the material. That means any blu-ray player or blu-ray program on your computer needs that key.

Since this key is all that's necessary to decrypt the video, managing to extract the key is all that's necessary to allow any other program to incorporate it. This is particularly easy if the people writing the programs/building the hardware haven't taken proper precautions to protect the decryption key, but there are also other ways and problems depending on context.

Of course, things are more complicated than this in reality, but the necessity of distributing the decryption information is the main problem.