I reconfigured the firewall on my server this weekend and I had some trouble getting NFS to work right so I decided to document my process here in case I ever have to do it again. I think the configuration files will be in the same place on all Debian-based distros but I didn't check since I've still got Ubuntu 16.04 on my file server.
A picture I took of my little power hog. Some rights reserved: cc by-sa
I've got a little Arduino project that I run off a 9V battery and I've noticed that it chews through batteries a lot faster than I expected it to — sometimes a battery lasts less than 24 hours. To figure out what was going on I hooked the project up to my power supply and discovered that it draws about 65 mA at 9V, which is a little more than half a watt. There are some LEDs connected to the board but even without those the Arduino Uno all by itself draws 49 mA, which seems way too high to me. I did a little research and testing and I was able to get it down to 36 mA without changing the hardware at all and I hope to get it lower than that with a different battery.
I'll preface this by saying that if you just want encrypted email and don't mind having a new email address then your best bet is to just use something like ProtonMail. It automatically generates and manages keys for you so it can encrypt mail to other people with keys and decrypt encrypted mail sent to you. If you don't want to bother setting it up yourself and you're OK with the limitations of their system then it's probably your best choice. If you'd like to know how to use GPG and how you can use it to encrypt whatever you want then read on.
If you use Tor then you've probably noticed that some .onion sites have addresses that don't look totally random, like facebookcorewwwi.onion or demonhkzoijsvvui.onion. Tor addresses are supposed to be randomly-generated — how do these have words in them?
Tor hidden services are useful for protecting privacy, but Tor users still have to rely on exit node operators to pass traffic from the Tor network to the web. Tor hidden services are designed to allow people to share websites with each other without either party revealing too much information about themselves. Another benefit of hidden services is that users can access them without going through an exit node, a weak point in the network's privacy protection and a resource with limited bandwidth.