I wanted to do this but with Blu-ray’s. My goal was to build a library of every movie ever made that was worth seeing. It seemed like 2018 was a good time to do this since good movies have apparently stopped being made. Anyway, If you wanted to watch tons of good movies, you would normally end up paying tons of money to rent it from iTunes. And even then you only get to see it once and you have to have an internet connection. And streaming services don’t have even a fraction of the selection needed. But Netflix’s mail dvd service seems to have every movie I can think of. So why not open a few Netflix accounts, order disks in the mail and just save all the disk images? It seemed like a good idea until I looked into Blu-ray copy protection. Of course, I wanted to have my library consist of only the highest quality and highest fidelity so Blu-ray’s were called for. But Blu-ray copy protection is devious, ingenious and very effective. Each disk consists of two regions: A region that holds encrypted movie data and a region that holds a key. It is illegal for players to be sold that read the key and then forward it to user-facing interface like a computer. Players must always only read the key only in order to use it internally to decrypt the movie data. This stops all legitimate entities from selling players that reveal the key to the user. But what about the illegitimate entities that might want to sell modified players that provide the key? Or just publish keys online? Well, the key on the disk is itself actually encrypted. And it is encrypted in such a way that multiple keys can decrypt it. Blu-ray players come with special hardware that is flashed with a key at the factory. This hardware uses that key to decrypt the Blu-ray’s key. In the event that a key is compromised and published online, or used widely in any way, that key is depreciated and all Blu-ray’s from that point onward contain keys that cannot be decrypted with the compromised hardware key. Instead, a newer key is used. This new key is still able to decrypt all the old Blu-ray keys as well as all the new ones. This effectively defeats people publishing keys online. It’s ingenious in that the people who conceived it realized that the only time key compromise is a problem is when those keys are disseminated widely, and that when keys are disseminated widely they are easy for authorities to detect. If you want to get perfect rips of any blu-Ray you might come across, you are forced to go through the pain of probing the hardware yourself to get that key, which is quite difficult. There’s no way around it.