passphrase.js (for browsers)

A (BIP-39 compatible) Base2048 Passphrase & Key Generator for browser JavaScript.

Lightweight. Zero dependencies. 20kb (17kb min, 7.4kb gz) ~150 LoC.

(most of the package weight is due to the base2048 word list)

<script src="https://unpkg.com/@root/passphrase"></script>
<script type="module">
  "use strict";

  let Passphrase = window.Passphrase;

  let passphrase = await Passphrase.generate(128);
  // often delay margin arch
  // index wrap fault duck
  // club fabric demise scout

  let keyBytes = await Passphrase.pbkdf2(passphrase);
  // Uint8Array[64] (suitable for use with importKey for AES, etc)

  let fooKeyBytes = await Passphrase.pbkdf2(passphrase, "foo");
  // Uint8Array[64] (a completely different key, determined by "foo")
</script>

Target Entropy	Number of Words	Total Bits
128-bit	12 words @ 11 bits each	= 132 bits (128 bits + 4-bit checksum)
160-bit	15 words @ 11 bits each	= 165 bits (160 bits + 5-bit checksum)
192-bit	18 words @ 11 bits each	= 198 bits (192 bits + 6-bit checksum)
224-bit	21 words @ 11 bits each	= 231 bits (224 bits + 7-bit checksum)
256-bit	24 words @ 11 bits each	= 264 bits (256 bits + 8-bit checksum)

Features & Use Cases

• Base2048 (BIP-0039 compliant)
• Easy to retype on different devices
• Seed many, distinct keys from a single passphrase
• Keys for AES Encryption & Decryption
• Air Gap security
• Cryptocurrency wallets

API

• generate
  • encode
• checksum
  • decode
• pbkdf2
• base2048.includes

Passphrase.generate(bitlen)

Generate a "Base2048" passphrase - each word represents 11 bits of entropy.

await Passphrase.generate(bitLen); // *128*, 160, 192, 224, or 256

Passphrase.encode(bytes)

Encode an array of 16, 20, 24, 28, or 32 bytes (typically a Uint8Array) into a passphrase using the Base2048 word list dictionary.

let bytes = Uint8Array.from([0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255]);

await Passphrase.encode(bytes);
// "abstract way divert acid useless legend advance theme youth"

Passphrase.checksum(passphrase)

We all make mistakes. Especially typos.

Running the checksum can't guarantee that the passphrase is correct, but most typos - such as brocolli instead of broccoli - will cause it to fail, so that's a start.

let passphrase = "often delay margin arch ...";
await Passphrase.checksum(passphrase); // true

let passphrase = "often delay margin arch TYPO";
await Passphrase.checksum(passphrase).catch(function (err) {
  // checksum failed?
  throw err;
});

Passphrase.decode(words)

Decode an string of space-delimited words from the Base2048 dictionary into a Uint8Array.

This will throw an error if any non-Base2048-compatible words are used, or if the checksum does not match.

let words = "abstract way divert acid useless legend advance theme youth";

await Passphrase.decode(words);
// Uint8Array[12] <0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255>

Passphrase.pbkdf2(passphrase, other)

Generate a private key seed or encryption key based on the passphrase and some other string - whether a salt, a password, another passphrase or secret, or an id of some kind.

await Passphrase.pbkdf2(passphrase, other || ""); // Uint8Array[64]

Passphrase.base2048.includes(word)

Check if a given word exists in the base2048 dictionary.

Passphrase.base2048.includes("broccoli"); // true

Passphrase.base2048.includes("brocolli"); // false

Get all misspelled words

"hammer spoon brocolli zoo".split(" ").filter(function (word) {
  return word && !Passphrase.base2048.includes(word);
});
// [ "brocolli" ]