A Yubikey is a small hardware device that you install in USB port on your system. Its main use is to provide multifactor authentication (MFA) when connecting to various websites that support it. So instead of having the site text/email you a six digit code and then typing that code into a form on the site, you can just touch the sensor on the yubikey to send a MFA code - much simpler. As MFA is implemented by more and more sites, this can be a very handy device. One nice side benefit is that the key can be removed from your laptop, so in theory, even if someone has access to your laptop and your passwords, without the key they will not be able to get into sites that you have configured . Yubikey is supported on many major sites. The main ones I used it on are GitHub and AWS