How encryption for Cinema Movies works

Re:How encryption for Cinema Movies works by jackjeff on Monday April 21, 2025 @05:12AM (#43749829)

> The video stream is encoded as one single JPEG2000 picture per frame. Each frame is encrypted with the same static AES key.

Is this not a problem? It’s not a good idea to reuse the same key to encrypt very similar files. Similar to ECB. See the famous penguin https://words.filippo.io/the-ecb-penguin/

I’m surprised they don’t use something like XTS commonly used for disk encryption. It derives a unique key for each block/frame and allow you to access each individual blocks/frames non sequentially.

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Re:How encryption for Cinema Movies works by perryflynn on Monday April 21, 2025 @06:32AM (#43750296)

No. They use a unique IV for each frame:

> Every Frame is using a unique IV (Initialization Vector), which ensures that the AES Block Cipher generates always different cipher texts and makes brute force harder. This works similar to a Password Salt.

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Re:How encryption for Cinema Movies works by jackjeff on Monday April 21, 2025 @07:43AM (#43750805)

Oh thanks. I missed that. I guess that works pretty well too!

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