One app invents and remembers a different long password for every account, so a break-in at one company cannot open all the others.
The drawing that proves the sentence above. It is the same card that is in the book.
Think of it as
a locksmith who keeps every key but only opens for you.
For example
You have one password you remember. Everything else is a long jumble you have never seen and never need to.
This is one card out of 275.
The hundred words you meet most are free — the whole set, animated, in one file that works with no internet.
Volume 1 has all 275 in fifteen chapters, with Staying Safe the largest chapter on purpose.