Diceware passphrase generator

A Diceware passphrase is a sequence of randomly chosen common words, such as correct-horse-battery-staple style phrases. Because the words are chosen randomly from a large list, passphrases are very strong yet much easier to remember and type than random character passwords. This generator creates them with your chosen number of words and separator.

How to use it

1. Choose how many words, 6 or more for important accounts.
2. Choose a separator such as a space, hyphen or period.
3. Generate and copy the passphrase, then store it in your password manager.

How strong is it?

The classic Diceware list has 7,776 words, one for each result of rolling five dice. Each word adds log2(7776) = 12.9 bits of entropy.

• 4 words: about 51.7 bits
• 5 words: about 64.6 bits
• 6 words: about 77.5 bits, a good choice for master passwords
• 7 words: about 90.5 bits

At 77.5 bits, an attacker guessing a trillion times per second would need on average more than two thousand years to find it. The strength comes from the randomness of selection, not from the words being obscure.

Rules for real security

• Do not change the words or choose your favourites; human choice destroys the randomness.
• Use a new passphrase for each important account, and a password manager for the rest.
• Extra capital letters or symbols add little; an extra word adds far more.

Words are selected with the browser's cryptographically secure random generator and never leave your device.