What I am talking about hers is definitely focussed only on "fingerprint known content", as that is the goal of the "figure out which Netflix movie I am watching" use case (as well as the "what model am I watching on myFreeCams/Chaturbate" use case, which might feel worse ;P... it is also the "what video am I watching on PornHub" use case, but that's inherently harder as there are so many many videos and they are often super short: much harder than the moderate catalog of long movies and tv shows on Netflix or the comparatively scant number of available live feed on camsites).

That said, as noted by someone else on this thread, there has been some work done figuring out what people are saying by analyzing encrypted speech packets; but I imagine that kind of technique would be almost impossible to pull off with these segments on the order of multiple seconds long, and including the video in the stream would seem to make that a total non-starter.

Well one of the things that paper does is they just go fetch the index.

Every Netflix client that is watching say 1080p Rick & Morty s1e2 fetches an index of the bits that make up that video, and then fetches the relevant chunks of data.

So if you just fetch that index, no need to "watch" the video, you know OK 1390450 bytes is the 1st chunk of data making up that video, and then 2046917 bytes is the 2nd chunk. When you see that somebody fetched 1390450 bytes of encrypted data from Netflix, they're probably watching s1e2 of Rick & Morty in 1080p. When they fetch 2046917 bytes of encrypted data that confirms it.

So it's "non-novel" but they don't need to (relatively expensively) actually watch the videos they want to match. It's likely any sophisticated adversary has an index of all the common videos from sites like Netflix, the Play Store, Disney+ and so on.

There is definitely more a client could do to make this harder, but there'd be a sharp trade-off where to make it impossible for passive eavesdroppers to know what you saw costs both you and the "broadcaster" a lot of bandwidth, and bandwidth ain't free.

I'd like to see Netflix at least gently stroll in that direction, maybe use some TLS padding to make it a bit harder to do this trick, but I don't expect them to set off at a sprint and ruin their profitability in pursuit of a non-goal.

> there'd be a sharp trade-off where to make it impossible for passive eavesdroppers to know what you saw costs both you and the "broadcaster" a lot of bandwidth, and bandwidth ain't free

Off the top of my head: if you took a live streaming approach along the lines of live TV, or indeed Google Stadia/GeForce Now/OnLive, then you could presumably make the traffic patterns invariant over what was being watched. You'd need to ensure the bitrate didn't drop during low-detail scenes, I suppose, similar to what you mentioned re. Skype below.

That approach would of course be far more intensive on server resources, but I'm sure a similar level of privacy could be achieved without such inefficiency.