Passphrase Generator

About Passphrase Generator

A passphrase is a sequence of random words used as a password — easier to remember than a string of random characters, yet statistically stronger. The classic example is "correct-horse-battery-staple" from the XKCD comic by Randall Munroe.

Entropy measures unpredictability in bits. Each additional word multiplies the search space exponentially: a 4-word phrase from a 170-word list gives around 28 bits per word, totalling ~112 bits — far beyond what brute-force attacks can reach. Adding capitalisation, numbers, and symbols pushes entropy even higher.

The estimated crack time assumes an attacker running one trillion (10¹²) password guesses per second — roughly the upper end of modern GPU cluster speeds. In practice most attacks are far slower.

All generation happens entirely in your browser using the Web Crypto API's Math.random() fallback. No passphrase is ever transmitted to any server.