Why Use a Passphrase?
The concept was popularized by the famous XKCD comic: four random common words strung together create a password that is both highly secure and easy to remember. The math is simple — with a word list of 7,776 words, each word adds about 12.9 bits of entropy. Five words give you ~64 bits, which would take centuries to crack.
Passphrases vs. Traditional Passwords
A 10-character random password like X7#mK9$pL2 has about 65 bits of entropy but is nearly impossible to memorize. A 5-word passphrase like Marble-Sunset-Bicycle-Ocean-Thunder has similar entropy but you can visualize and remember it easily.
Tips for Using Passphrases
- Never use a phrase from a book, song, or movie — use random words
- Add a number or special character for sites that require them
- Use at least 5 words for important accounts
- Store your passphrases in a password manager for convenience
- Use a different passphrase for every account