Password Generator

crypto.getRandomValues, the browser’s cryptographic RNG. Each character index is drawn from a 32-bit value, and any value that falls in the incomplete final bucket is thrown away and redrawn rather than folded back with a modulo, that fold is what would make the first few characters of the pool slightly more likely than the last few. Math.random appears nowhere on this page.

Length × log2(pool size), which is the honest number for characters drawn independently and uniformly. The default 20 characters over the full 86-character pool comes to 128.5 bits. In passphrase mode it is words × log2(200), so seven words is 53.5 bits, and appending a digit adds 3.3. What the figure does not describe is a password you chose yourself: the moment a human picks the characters the distribution stops being uniform, and the arithmetic stops being true.

No. crypto.getRandomValues runs inside this tab and no request is made when you press Regenerate, disconnect from the network and the button still works. Nothing is written to storage either, so closing the tab is the entire delete process.

Slightly. Dropping I, l, 1, O, 0 and o takes the pool from 86 characters to 80, about 2 bits at length 20.

Every character is drawn independently from the pool you selected, so a short one can miss a class by chance. Forcing one of each would shrink the set of possible passwords and quietly lower the entropy shown above, so the tool does not do it. Regenerate, or raise the length.