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Diceware & Random-Word Passphrases

The method behind picking random words for a passphrase — and why a good random source matters more than dice.

Coined in 1995 by Arnold Reinhold, diceware generates a passphrase by rolling physical dice: five rolls give a five-digit number (11111–66666), which is looked up in a numbered word list to pick one word. Repeat six times and join the words — the passphrase is only as secure as the dice and the list are random.

Why a CSPRNG beats physical dice

Dice are genuinely random, but slow and easy to record or observe. This site's passphrase generator does the equivalent job digitally, using crypto.getRandomValues() — the browser's cryptographically secure random source — to pick each word from a 1,356-word list. That's about 10.4 bits of entropy per word, so a six-word passphrase carries roughly 62 bits, and an eight-word one over 83 bits.

Sample words from our list

river tiger lamp fabric ocean coral gravel amber willow ember thistle quartz

Want the full numbered list?

If you specifically want to roll physical dice, the EFF publishes a free, professionally vetted 7,776-word numbered diceware list (and a shorter, easier-to-type variant) — the modern standard, designed to avoid similar-sounding or hard-to-spell words.

Related terms: Passphrase · Entropy · CSPRNG

FAQ

Is our passphrase generator technically diceware?

Not literally — it doesn't map words to dice-roll numbers, so you can't reproduce it with physical dice. It uses the same principle (uniformly random word selection) with a cryptographically secure generator instead, which is at least as strong.

Is a shorter word list less secure?

A shorter list means slightly less entropy per word (about 10.4 bits for 1,356 words versus about 12.9 bits for EFF's 7,776-word list), but adding one extra word more than makes up the difference — six words from our list beats five from a longer one.

Should I write my passphrase down?

If you must, store it somewhere physically secure and separate from any device — but a password manager with a strong master passphrase is safer and more practical for everything except that one master phrase itself.