Diceware Generator

// EFF Diceware wordlist: 7,776 words
// Each word is selected by a 5-digit dice roll (11111-66666)
import { EFF_WORDLIST } from './diceware-wordlist.js';

function rollDice5() {
  // Simulate rolling 5 six-sided dice
  // Each die: 1-6, combined as a 5-digit number: 11111 to 66666
  const dice = new Uint8Array(5);
  crypto.getRandomValues(dice);
  return Array.from(dice)
    .map(d => (d % 6) + 1)  // Map 0-255 to 1-6
    .join('');
}

function generateDicewarePassphrase(wordCount = 6) {
  const words = [];
  for (let i = 0; i < wordCount; i++) {
    const roll = rollDice5();
    const index = parseInt(roll, 10) - 11111; // Convert to 0-based index
    words.push(EFF_WORDLIST[index]);
  }

  const entropy = wordCount * Math.log2(EFF_WORDLIST.length);

  return {
    passphrase: words.join(' '),
    wordCount,
    entropyBits: entropy.toFixed(1),
    combinations: Math.pow(EFF_WORDLIST.length, wordCount).toExponential(2)
  };
}

// Usage
const result = generateDicewarePassphrase(6);
console.log(result.passphrase); // "walnut clarinet tumble prism orbit cobalt"
console.log(result.entropyBits); // "77.5"

// For users who prefer physical dice
function diceRollToWord(rolls) {
  // rolls: array of 5 numbers (1-6 each), e.g., [3, 1, 4, 1, 5]
  const rollString = rolls.join('');
  const index = parseInt(rollString, 10) - 11111;

  if (index < 0 || index >= 7776) {
    throw new Error('Invalid dice roll: must be 5 dice, each 1-6');
  }

  return EFF_WORDLIST[index];
}

// Example: user rolls 3,1,4,1,5 on physical dice
const word = diceRollToWord([3, 1, 4, 1, 5]);
console.log(word); // The word at position 1354 in the EFF list

// Entropy per word: log₂(7776) ≈ 12.92 bits
// 6 words = 77.5 bits total