Guide 01
How QR codes actually work
Finder patterns, modules, Reed–Solomon error correction, masks and the quiet zone, in the order a camera meets them.
The thinking behind the tools.
Six short guides, one per instrument. Each explains the thing the generator is built on, in enough depth that you could check the maths yourself, and no further.
Read the guide
Guide 02
Password entropy, explained
What a bit is, how pool size and length become a number, and how many bits you actually need.
Guide 03
How lottery odds are calculated
Combinations, bonus balls, why partial matches pay out, and what a ticket is actually worth.
Guide 04
Base64, explained properly
Six bits at a time, why the output grows by a third, what the equals signs mean, and why it is not encryption.
Guide 05
How PIN codes get guessed
Lockouts, the twenty codes that cover a quarter of all PINs, birthdays, and what a good habit looks like.
Guide 06
Where the randomness comes from
Math.random against the Web Crypto API, what makes a number cryptographic, and why rejection sampling matters.