Cannot play DRM content in browsers (honestly, I've looked)

Unfortunately I don't think it is currently possible (as of March 2017) to natively watch any of these in linux without exposing your system to security vulnerabilities, since they required the hal-flash package with flash 11.*, and this no longer works in more recent flash versions.

One workaround that I have used to watch HBOGo (with somewhat limited success) is to run android-x86 in virtualbox and use their app. Another potential workaround is to downgrade to flash 11.* in firefox and install hal-flash, but running an out of date flash plugin is a tremendous security risk (and recent versions of firefox will block it by default because it is out of date) and there is likely no simple way to do this through regular software channels on ubuntu or most other distros.

Sources: https://github.com/cshorler/hal-flash/issues/26 for a discussion on this exact issue.

From adobe's announcement itself it seems possible that this will never work again in the NPAPI flash plugin: "Because this change is primarily a security initiative, some features (like GPU 3D acceleration and premium video DRM) will not be fully implemented." https://blogs.adobe.com/flashplayer/2016/08/beta-news-flash-player-npapi-for-linux.html (they seem to imply that DRM works on PPAPI flash, but this is unfortunately also not the case as these sites have never worked with chrome's flash).

Thanks to everyone for this detailed post about this matter. It seems that as of March 2018 there is no solution for read DRM and Flash contents - ie HBO Go in my case. I tried everything with my ubuntu 16.04 , hal ... hbo still resist.

It seems that Firefox clearly says that Flash and DRM is not supported.

https://support.mozilla.org/en-US/kb/enable-drm?as=u&utm_source=inproduct