Here is an example of how to securely encrypt files under GNU/Linux, using GNU Privacy Guard, with particular respect to revelations made about the NSA by Edward Snowden and others.
Like most iD titles, RTCW was ultimately released under the GPL, and is thus available as a GNU/Linux native game. Installing it under Gentoo is as simple as "emerge games-fps/rtcw", but unfortunately the game itself no longer works in modern GNU/Linux systems. This is only to be expected with proprietary software that becomes abandoned, and would affect the operation of that software on any OS, but naturally it doesn't have to be that way with Free Software, which can be revived at any time, even years later.
Here's a script I wrote to "fix" videos I ripped from DVD/BD, where the rip is too big to fit on a FAT32 formatted flash drive (my Smart TV doesn't recognise NTFS or ext2/3/4 filesystems), has the wrong resolution/aspect, and/or possibly contains multiple language audio tracks I don't need (my Smart TV also doesn't play DTS audio).
First, here’s what he didn’t say:
Linux development is another story altogether. Even though Valve is now actively pursuing the Linux market, id has been there before, and just has not seen positive results. Remember how many past titles from id actually ran on Linux, and for how long these were supported? John says that Linux development simply does not pay the bills. It creates goodwill among the Linux crowd, but that is about it.
I watched Carmack’s keynote ... all three hours and thirty-six minutes of it. Twice. And took notes.
The first thing that needs to be said about the above quote is it’s actually by Josh Walrath, Managing Editor of PC Perspective, not Carmack. The only thing Carmack said about Linux was this:
Not nearly as many people are interested in paying for games on the platform.
That’s it. No mention of "goodwill", a lack of "positive results" or "paying the bills". The only mention of "past titles" was his reference to the fact that Linux "just hasn't carried its weight compared to the mac"... on Quake Live, which was actually an abysmal failure for reasons entirely unrelated to Linux. In other words Linux accounts for comparatively fewer sales of id's games. Fewer, not "none", not a total lack of "positive results", not Linux isn't "paying the bills", and not "we're going bankrupt because of Linux". That's just pure hyperbole. Moreover, at no point did Carmack explicitly state nor even imply that id were abandoning Linux, as many seem to have inferred from that article.
People often conflate proprietary software with commercial software, believing software can only be sold if it's proprietary, because a proprietary license is the only thing that prevents people from using software without paying.
In fact that is not the case at all. On the one hand, proprietary software is used all the time in violation of its license, as the industry's own figures demonstrate.
So clearly proprietary licensing is no guarantee of payment, therefore the license itself is irrelevant to selling software for profit.