Aaruni's Blog v 3.0

I have always been obsessed with computers. Unfortunately, as a child, I never could pick the top of the line parts for any of my computers. They were either hand-me-downs, or decked out to meet my needs, which, at the time, fell well short of my wants.

A Truly Grand Upgrade

I got my first full time job in 2023. The first thing I did with these newfound funds was buy furniture in my new apartment. The second thing I did bought a monster of a computer. A shiny new ryzen processor, double the memory I used to have, and, for the first time since 2008, in a desktop form factor. Before this, I had a relatively beefy Asus ROG gaming laptop, mostly for the high end CPU and good build quality. My new computer was 3 to 7 times faster!

Authentication

Authentication is any process that verifies and validates the identity of a client. Any login process is a type of authentication. Traditionally, authentication is done via a username and a password.

Multi Factor Authentication

Multi factor authentication (MFA) uses multiple factors to establish identity, instead of a single one, as in the classical case. These factors can be

• Something you know (e.g., password)
• Something you have (e.g., a phone)
• Something you are (e.g., biometrics)
• Somewhere you are (e.g., GPS coordinates)

With a sane setup, for the vast majority of daily activities, 2 Factor Authentication (2FA) is sufficient.

One Time Password

A One Time Password (OTP) is, as the name suggests, a single use password. It is most frequently used as a second factor in a 2 Factor Authentication scheme. It provides the “something you have” factor: the device providing the password.

Time based One Time Password

A Time based One Time Password (TOTP) is a One Time Password which uses the current time to generate the One Time Password. This means that TOTPs do not need a working network connection, and can still make a valid OTP on demand. Mathematically, a TOTP is just a function which takes two inputs, a seed, and the time. If the seed is shared ahead of time, as a pre shared secret, TOTP can be, and is used, as a complete and secure replacement for classical forms of OTP.

Tail-what?

Tailscale is a project by Tailscale Inc which creates a mesh network of your devices. It allows all the devices on your tailscale network, the “tailnet”, to talk to each other direclty, in a peer to peer manner. It does not matter if your devices are separated by the internet, or a NAT, or even a CGNAT: tailscale can break through and create a functional tunnel between each of your devices. It works by employing Wireguard behind the scenes to create a tunnel from each device, to every other device in your tailnet. For 9 devices, that means 90 tunnels have to be created and maintained, and without tailscale, this operation would be MANUAL! The full breakdown of exactly how Tailscale works can be found here.

As part of my work, I’m heavily using ostree. Ostree is a git like content addressed store for filesystem trees. Its a really cool technology for distributing software, and is used by many major players in the industry : GnomeOS, rpm-ostree, flatpaks, and so on. While ostree has capability of deploying entire OS trees (hence the name), it can also be used in “user mode” (as opposed to “host mode”), where it manages only a target user repository, instead of the entire host. (Fun fact, ostree has the ability to juggle between different versions of the OS, or even different OSs!)