Passphrase generator

Six random words stick after a couple of readings, yet cannot be guessed. A 2048-word list gives exactly 11 bits per word, and the trailing number adds about seven more — switch it off if the form does not demand a digit.

Space — new password · C — copy · M — hide

Password strength dial
0bits

Online guessing (100/sec)
Offline, GPU rig (10¹⁰/sec)
Nation-state scale (10¹⁴/sec)

Password length

Character sets

Passphrase settings

A 2048-word list gives exactly 11 bits per word (the Diceware method). Six words are 66 bits, eight are 88. The words are drawn by a cryptographic generator, not by a human — that is the whole point.

Fine tuning

“Safe symbols only” keeps !@#$%^&*_-+=? — almost every site accepts them and they do not break shell commands, CSV or SQL.

Recent passwords (this tab only)

What happens to your password

The password is assembled in your browser from the cryptographic randomness source crypto.getRandomValues with rejection sampling, so every character is equally likely.

The page never sends passwords to a server, never writes them to browser storage and drops the history when the tab closes.

The method

Why six random words beat “Q!7x”

Diceware was proposed by Arnold Reinhold in 1995: the words are drawn by lot from a list everyone can see. The secret is not a hidden dictionary — it is open — but the fact that a human does not do the choosing.

Our list holds 2048 short words, exactly 11 bits each. An attacker who knows both the list and the method still has to work through 20486 ≈ 7.4·1019 options for a six-word phrase.

The real advantage is typing. A phrase like “river-fog-cedar-lantern-bridge-owl” can be entered on a TV, read out over the phone and memorised in two readings. That is exactly why it makes the best master password for a vault or a key for an encrypted disk.

How many bits

Phrase length and strength

WordsEntropyOffline cracking
444 bitsabout 30 minutes
555 bitsabout 2 months
666 bitsabout 370 years
777 bits750 thousand years
888 bits1.5 billion years

Calculated for an attack at 10¹⁰ guesses per second against a stolen hash database. Appended digits add another 6.6 bits.

Which word list to pick

English words work everywhere. The Cyrillic list is stronger against English-only dictionaries but many services reject non-Latin characters, so there is also a transliterated mode: the same words rendered as reka-tuman-kedr.

Questions

Frequently asked questions

Why is a passphrase better than a random string?

At equal entropy it is just as strong, but you can actually memorise it and type it without mistakes on a TV remote or a phone. That makes it the prime candidate for a password-manager master password or a disk encryption key.

How many words should I take?

Six words are 66 bits, seven are 77, eight are 88. Use at least seven for a master password; six plus digits is plenty for an ordinary service.

Can I invent a phrase myself?

No. People pick words from their active vocabulary in a predictable order and glue them into a meaningful sentence — such phrases fall orders of magnitude faster. The value of the method lies in the dice.

Why exactly 2048 words?

It is a power of two: log₂(2048) is exactly 11 bits per word, so the entropy is easy to compute in your head. The words are short and unambiguous, with no homophones or tricky spelling.

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