Guides
The tools make choices for you — length, character set, sampling method, decoding order. These pages explain what those choices are, so you can tell whether the default is the right one for your case.
Every guide is written against something verifiable: the entropy formula, the actual rejection-sampling loop, the ISO/IEC 18004 structure of a QR symbol. Where a number is an estimate — crack time, for instance — the assumption behind it is stated rather than buried, because a crack time without its attack speed is meaningless.
Updated October 21, 2026. If a guide does not answer your question, the related tool page usually carries a shorter version of the same answer in its FAQ.
Passwords (4)
How long does it take to crack a password? The answer depends almost entirely on two things: how the password is stored, and how long it is. Password generator vs password manager: which do you need? They solve different halves of the same problem, and using one without the other barely helps. What actually makes a password strong Four properties matter. Most of the advice people repeat is about the least important one. What is a passphrase, and when is it better? Words trade density for memory. Whether that is a good trade depends on whether you have to type it.
Random numbers (2)
QR codes (4)
How to scan a QR code on an Android phone Android has three built-in scanners. None of them reads an image from your gallery. How to scan a QR code on an iPhone The Camera app does it natively. The interesting case is a code that exists as a photo. QR code security risks and how to check one A QR code is a link you cannot read. That is the entire attack surface. Why won't my QR code scan? Almost every failed scan comes down to one of eight causes. Here is how to tell which.