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Diceware Passphrase Generator

Generate secure, memorable passphrases using the Diceware word list — strong enough for real security use.

About Diceware Passphrase Generator

The Diceware Passphrase Generator creates secure, memorable passphrases by randomly selecting words from the EFF (Electronic Frontier Foundation) Diceware word list using a cryptographically secure random source (Web Crypto API). A 5-word Diceware passphrase has approximately 65 bits of entropy; 6 words gives ~78 bits; 7 words ~91 bits. These are strong enough for disk encryption, account security, and master passwords. Unlike random character passwords, Diceware passphrases are much easier to memorize and type while providing equivalent or better security. The tool shows the entropy in bits and estimated crack time so you can choose the word count that meets your security requirements.

Why use Diceware Passphrase Generator

  • Uses the EFF Diceware word list — designed for maximum memorability.
  • Cryptographically secure random source (Web Crypto API).
  • Shows entropy in bits and crack time so you can verify the security level.
  • Passphrases are more memorable than random character passwords at equal entropy.
  • Uses the EFF Diceware Large Wordlist — designed in 2016 specifically for maximum memorability and unambiguous spelling.
  • Cryptographically secure random source via Web Crypto API — equivalent to rolling physical dice.

How to use Diceware Passphrase Generator

  1. Set the number of words (default 6, recommended minimum 5).
  2. Click Generate to produce a new passphrase.
  3. The entropy in bits and estimated crack time are shown below.
  4. Click Copy to copy the passphrase to your clipboard.
  5. Set the number of words (default 6, recommended minimum 5 for general use, 7+ for high-security master passwords).
  6. Optionally choose a separator: space (default), hyphen, or no separator.
  7. Click Generate to produce a new passphrase using cryptographically secure randomness.

When to use Diceware Passphrase Generator

  • Creating a master password for a password manager.
  • Generating a passphrase for full-disk encryption (VeraCrypt, LUKS).
  • Setting a memorable SSH key passphrase.
  • Creating account passwords that must be typed rather than copied.
  • Creating a master password for a password manager (Bitwarden, 1Password, KeePass) — must be both strong and memorable.
  • Generating a passphrase for full-disk encryption (VeraCrypt, LUKS, FileVault, BitLocker recovery key).

Examples

5-word passphrase (~65 bits entropy)

Input: Word count: 5, Separator: space

Output: correct horse battery staple jukebox Entropy: ~64.6 bits — Crack time at 1 trillion guesses/sec offline: ~877 years

6-word passphrase (~78 bits, recommended)

Input: Word count: 6, Separator: hyphen

Output: tundra-mosaic-fragile-pulse-hatchet-quartz Entropy: ~77.5 bits — Crack time at 1 trillion guesses/sec offline: ~6.8 million years

7-word high-security passphrase (~91 bits)

Input: Word count: 7, Separator: space

Output: harvest crimson lattice ember waltz puddle hexagon Entropy: ~90.4 bits — Effectively uncrackable by current and foreseeable hardware

4-word low-stakes passphrase (~52 bits)

Input: Word count: 4, Separator: space

Output: prelude orbit timber valley Entropy: ~51.7 bits — Acceptable for low-value accounts only; not for master passwords

Tips

  • 5 words (~65 bits) is the recommended minimum; use 6-7 words for master passwords and high-value accounts.
  • Don't manually edit the passphrase — even small substitutions reduce entropy below the calculated bits.
  • Memorize using visualization: turn the words into a vivid mental scene where each word interacts with the next.
  • If the first generated passphrase has hard-to-spell words, generate again — entropy isn't reduced by rerolling.
  • Hyphens are a good separator for systems that don't allow spaces (some web forms, command-line flags).
  • Avoid using the passphrase as a hint for itself or storing it near the system it protects.
  • Write the passphrase on paper only as a temporary memory aid; destroy the paper once you have it memorized.

Frequently Asked Questions

What is Diceware?▾
Diceware is a method for generating passphrases by rolling dice to select words from a numbered word list. This tool replaces physical dice with a cryptographically secure random number generator.
How many words do I need?▾
5 words (~65 bits) is a reasonable minimum. 6 words (~78 bits) is recommended for most security uses. 7+ words (~91 bits) for high-security master passwords.
Is this as secure as a random character password?▾
Yes. A 6-word Diceware passphrase (~78 bits) is as secure as a random 13-character password using all printable ASCII characters.
What word list is used?▾
The EFF Large Wordlist (7776 words, 5 simulated dice rolls), released in 2016. It was designed to contain only common, unambiguous English words for easy memorability.
Will my passphrase be logged or stored?▾
No. Generation is entirely local in your browser using the Web Crypto API. No passphrase or random data is sent to any server.

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Glossary

Entropy (bits)
A measure of unpredictability. Each bit doubles the search space; 65 bits means ~3.7 × 10^19 possible passphrases — far beyond brute-force range for offline attacks at trillion-guesses-per-second.
EFF Large Wordlist
A 7,776-word wordlist published by the Electronic Frontier Foundation in 2016, designed for Diceware and curated for memorability, unambiguous spelling, and a minimum 3-character length per word.
Diceware
A passphrase-generation method invented by Arnold Reinhold in 1995 that selects words from a numbered list using dice rolls (or a CSPRNG) — five dice rolls give a 5-digit index into a 7,776-entry list.
CSPRNG
Cryptographically Secure Pseudo-Random Number Generator — a randomness source whose output cannot be predicted even with knowledge of past outputs; the Web Crypto API exposes a CSPRNG to browsers.
Brute-force attack
Trying every possible passphrase until the correct one is found. At 1 trillion guesses per second (current high-end offline rate), 65 bits of entropy takes ~877 years on average.
Passphrase strength
Often measured in bits of entropy; 60+ bits resists online attacks, 70+ resists most offline attacks, 80+ is considered safe against well-funded adversaries for the foreseeable future.
Master password
The single passphrase that decrypts a password manager's vault — the most critical secret a user owns. Recommended 6-7 Diceware words minimum.
Web Crypto API
A modern browser standard (window.crypto) for cryptographic primitives; getRandomValues() returns truly unpredictable bytes suitable for key generation and secure passphrase creation.