Day 9’s problem statement is convoluted - the “ah maybe that’s why I don’t usually do Advent of Code” kind of convoluted, but let’s give it a go anyway.

So, we have a series of numbers, like so:

35 20 15 25 47 40 62 55 65 95 102 117 150 182 127 219 299 277 309 576

And uh the first N numbers are a “preamble” and every number that comes after that must be the sum of any two of the numbers that come before it.

Background

im-promp-tu (im-ˈpräm(p)-(ˌ)tü)

1. made, done, or formed on or as if on the spur of the moment: improvised

2. composed or uttered without previous preparation: extemporaneous

Merriam-Webster

On March 18th, 2025, I thought I would look into self-hosted project management solutions — something kanban-y, but.. better?

In Veronica Mars and password hashes, from my new Tech As Seen On TV series, we’ve explored “cracking passwords” using brute-force methods, and then using rainbow tables, which was much, much faster.

But how do rainbow tables actually work? Let’s start at the beginning.

What’s a password hash?

A very simple design for an authentication system is to store passwords in clear text, say, in a file named password.txt:

I have obsessed about this long enough, I think it’s only fair I (and you!) get some content out of it.

When I started writing this article, I was working on my P99 CONF slides. Those slides happen to include some bits of code. And because I’m a perfectionist, I would like this code to be syntax highlighted, like this:

let addr: SocketAddr = config? ln = addr? config

Our catscii program does everything we want it to do, except that it’s a command-line application rather than a web server. Let’s fix that.

Enter axum

The documentation for the axum crate tells us how to make a basic web server, and we honestly don’t need much more than that.

So let’s add axum:

amos@miles:~/catscii$ cargo add [email protected] Updating crates.io index Adding axum =0.6 to dependencies. Features: + form + http1 + json + matched-path + original-uri + query + tokio + tower-log - __private_docs - headers - http2 - macros - multipart - w

Because I started accepting donations via GitHub Sponsors, and because donating at the “Silver” tier or above gives you advance access to articles and your name in the credits, I need to interface with the GitHub API the same way I do the Patreon API.

Because I’d rather rely on third-party identity providers than provide my own sign up / log in / password forgotten / 2FA flow, user identifiers on my website are simply {provider}:{provider_specific_user_id}:

My watch has a “Noise” app: it shows $\mathrm{d}\mathrm{B}$, for decibels.

My amp has a volume knob, which also shows decibels, although.. negative ones, this time.

And finally, my video editing software has a ton of meters — which are all in decibel or decibel-adjacent units.

I’ve been bragging about my website software for years! For… whew, it’s been 5 years!

I’ve been teasing folks about the cool things I did from the beginning — here are all the articles and series I’ve written that mention it:

• 2020: A new website
• 2021: Don’t shell out!
• 2022: Updating fasterthanli.me

Welp, I did it again - I released an album: it’s named *andfall, a play on the word “landfall”, and I wrote it in one week-end, for @McFunkyPants’ entry in the Ludum Dare 33 game jam.

It’s my first solo album, the previous ones were collaborations with @bigsylvain and @geckojsc. It feels a bit weird to release an album alone - there’s nobody to blame for the flaws, and nobody to praise for the good parts!

Welcome back and thanks for joining us for the reads notes… the thirteenth installment of our series on ELF files, what they are, what they can do, what does the dynamic linker do to them, and how can we do it ourselves.

I’ve been pretty successfully avoiding talking about TLS so far (no, not that one) but I guess we’ve reached a point where it cannot be delayed any further, so.