Passphrase Generator
Build a passphrase from the EFF short wordlist — 1296 short words, about 10.3 bits each, drawn in your browser and never sent anywhere.
bits = words × log₂(1296) ≈ words × 10.3
A passphrase is a password you can actually remember, and the reason it works is arithmetic rather than cleverness: each word is drawn at random from a list of 1296, so every word you add multiplies the number of possibilities by 1296 again. Six words from this list is roughly 62 bits — more than most people's hand-made passwords, and far easier to type. The drawing happens in your browser and the result is never sent anywhere.
How it is calculated
bits = words × log₂(1296) ≈ words × 10.3
The list holds exactly 6^4 words, which is 1296 — the number of outcomes of 4 dice, because it was built to be used with them. That is where the bits per word come from, and why the strength depends on the length of the list rather than on which words happen to come up.
Questions people ask
- How many words should I use?
- Six is a reasonable default at about 62 bits. EFF quotes eight words from this list as roughly 83 bits, which is the point where guessing stops being the attack anyone would choose.
- Why are the words so short?
- This is the short list, chosen so every word is at most five letters and easy to type without mistakes. The long list has 7,776 words and about 12.9 bits each, so it buys more strength per word at the cost of longer and rarer words.
- Why does my hyphenated passphrase look like it has an extra word?
- Because one word on the list is genuinely hyphenated: yo-yo. If it comes up in a hyphen-separated phrase the result reads as one word longer than you asked for. The word count and the strength are unchanged — pick a different separator if the appearance bothers you.
- Is 1296 words really enough to be safe?
- Yes, because the strength is 1296 raised to the number of words rather than multiplied by it. Four words already give 2.8e+12 possibilities, and each further word multiplies that by 1296.
- Can I just pick words myself?
- No, and this is the part that matters. The arithmetic above holds only if the words are drawn at random. Words a person chooses are drawn from a much smaller set, in an order somebody can guess, and the bits evaporate.
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