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Generate or convert random bytes into passphrases in Node and the browser.


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A JS library for generating random-yet-memorable passwords, either server-side in Node or in the browser. Each word provides 16 bits of entropy, so a useful password requires at least 3 words.

Because the wordlist is of exactly size 2^16, Niceware is also useful for convert cryptographic keys and other sequences of random bytes into human-readable phrases. With Niceware, a 128-bit key is equivalent to an 8-word phrase.


WARNING: The wordlist has not been rigorously checked for offensive words. Use at your own risk.

Sample use cases

  • Niceware can be used to generate secure, semi-memorable, easy-to-type passphrases. A random 3-5 word phrase in Niceware is equivalent to a strong password for authentication to most online services. For instance, +8svofk0Y1o= and bacca cavort west volley are equally strong (64 bits of randomness).
  • Niceware can be used to display cryptographic key material in a way that users can easily backup or copy between devices. For instance, the 128-bit random seed used to generate a 256-bit ECC key (~equivalent to a 3072-bit RSA key) is only 8 Niceware words. With this 8-word phrase, you can reconstruct the entire public/private key pair.

Usage in Node

To install:

npm install niceware

To generate an 8-byte passphrase:

const niceware = require('niceware')

// The number of bytes must be even
const passphrase = niceware.generatePassphrase(8)

// Result: [ 'deathtrap', 'stegosaur', 'nilled', 'nonscheduled' ]

Usage in browser

To use Niceware in modern browsers, include browser/niceware.js in a script tag. Niceware is then available in the window.niceware object.

<script src='niceware.js'></script>
  const passphrase = window.niceware.generatePassphrase(8)

Niceware uses window.{crypto, msCrypto}.getRandomValues for entropy in the browser.


NOTE: When used in the browser, Buffer is replaced with window.Uint8Array.

niceware ⏏

Kind: Exported constant

niceware.bytesToPassphrase(bytes) ⇒ Array.<string>

Converts a byte array into a passphrase.

Kind: static method of niceware

Param Type Description
bytes Buffer The bytes to convert

niceware.passphraseToBytes(words) ⇒ Buffer

Converts a phrase back into the original byte array.

Kind: static method of niceware

Param Type Description
words Array.<string> The words to convert

niceware.generatePassphrase(size) ⇒ Array.<string>

Generates a random passphrase with the specified number of bytes. NOTE: size must be an even number.

Kind: static method of niceware

Param Type Description
size number The number of random bytes to use

Niceware ports


Niceware was inspired by Diceware. Its wordlist is derived from the SIL English word list. This project is based on my work on OpenPGP key backup for the Yahoo End-to-End project.