I am trying to use Signal as a replacement for teleconferencing software like Zoom as much as possible in my work with clients. One thing I need to do sometimes is record video calls (always with consent of everyone involved of course). There is no native functionality in Signal for this, so I tried with OBS Studio on my Windows 11 laptop and learned that one needs to disable the Screen Security feature in Signal. Disabling screen security removes a layer of protection for all Signal content on that device though, so I was wondering if there was a more secure way to accomplish this. Thanks!
maybe Video Capture Card?
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HDCP is a risk here.
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HDCP on HDMI is, or at least pretty much was and I think still is, a joke. At least I have never had an issue using a cheap HDMI to USB video capture device on any HDMI source I have tried.
A way I have used to capture video has been to put a cheap HDMI splitter on the output of the source device. One output of the spitter is a display so the content is visible the other output of the spitter being the USB capture device. Only issue I have had is if the capture device and the display support different resolutions but that is something under your control.
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yeah I was jusat sayin that since Signal utilizes a form of DRM, an HDMI Capture Card that isnt kidding around on HDCP is a problem if you wanna keep the screen protection setting on in signal
but of course if it has problems that’s a seperate topic honestly but those curious here it is
Out of curiosity, I pulled a 2 way HDMI spitter and a HDMI to USB capture device out of my kit of potentially useful things that I have when helping people make public presentations and maybe want to record or stream them. These are no-label, generic, cheap items from the big A store on the Internet. I used those to tap into and record the HDMI going to my external display. I was running Signal on my MacBook with the Signal window on the external display. Using something like OBS would probably be much better, at least I’d have more control over inputs, etc., but I did the quick and dirty by using the “record screen” feature of the built in QuickTime player.
I found that Signal does not give you the option to make a video call to yourself, so I had to actually call someone I knew.
I borrowed my spouse’s phone and made a video call from my laptop to their phone. Capture and recording of the Signal call worked. I did have to fiddle with the MacBook system settings for microphone and speaker but not a big deal.
So, several take aways:
- If your opponent has physical access your hardware then they have the keys to the kingdom. (You should know that by now if you are following any security or privacy computer forum.)
- @enspIcIl could use a setup like this, at least on a Mac and probably on any other type of device, to record Signal video calls.
- You have to trust those you are communicating with. See, for example: The FBI spied on a Signal group chat of immigration activists, records reveal - News - Techlore Forum
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