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How encryption for Cinema Movies works

(serverless.industries)
230 points perryflynn | 2 comments | 20 Apr 25 17:52 UTC | HN request time: 0.415s | source
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jackjeff ◴[21 Apr 25 09:12 UTC] No.43749829[source]▶
> 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.

replies(1): >>43750296 #
1. perryflynn ◴[21 Apr 25 10:32 UTC] No.43750296[source]▶
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.

replies(1): >>43750805 #
2. jackjeff ◴[21 Apr 25 11:43 UTC] No.43750805[source]▶
Oh thanks. I missed that. I guess that works pretty well too!