crypto-keygen-suite/keyGen/otp/generateOCRA.js

Key generation utilities for cryptographic operations. YES I RENAMED IT. SIX STATE PROTOCOL!!! See its folder for all <3

import crypto from 'crypto';
import yargs from 'yargs/yargs';
import { hideBin } from 'yargs/helpers';

function padHex(hex) {
  return hex.length % 2 ? '0' + hex : hex;
}

function strToHex(str) {
  return Buffer.from(str, 'utf8').toString('hex');
}

function intToHex64(num) {
  let hex = num.toString(16);
  hex = hex.padStart(16, '0');
  return hex;
}

function dynamicTruncate(hmac) {
  const offset = hmac[hmac.length - 1] & 0xf;
  const binCode = 
    ((hmac[offset] & 0x7f) << 24) |
    ((hmac[offset + 1] & 0xff) << 16) |
    ((hmac[offset + 2] & 0xff) << 8) |
    (hmac[offset + 3] & 0xff);
  return binCode;
}

function generateOCRA({ suite, keyHex, counter, question, password, session, timestamp, digits }) {
  
  const suiteBuf = Buffer.from(suite, 'ascii');
  const sep = Buffer.from([0x00]);

  function hexPad(hex, length) {
    return hex.padEnd(length * 2, '0');
  }

  const counterBuf = counter ? Buffer.from(padHex(counter.toString(16)), 'hex') : Buffer.alloc(0);
  const questionBuf = question ? Buffer.from(question, 'ascii') : Buffer.alloc(0);
  const passwordBuf = password ? Buffer.from(password, 'ascii') : Buffer.alloc(0);
  const sessionBuf = session ? Buffer.from(session, 'ascii') : Buffer.alloc(0);
  const timestampBuf = timestamp ? Buffer.from(timestamp, 'ascii') : Buffer.alloc(0);

  const msg = Buffer.concat([suiteBuf, sep, counterBuf, questionBuf, passwordBuf, sessionBuf, timestampBuf]);

  const key = Buffer.from(keyHex, 'hex');
  const hmac = crypto.createHmac('sha1', key).update(msg).digest();

  const binCode = dynamicTruncate(hmac);

  const otp = (binCode % 10 ** digits).toString().padStart(digits, '0');

  return otp;
}

async function main() {
  const argv = yargs(hideBin(process.argv))
    .option('key', {
      alias: 'k',
      type: 'string',
      demandOption: true,
      describe: 'Secret key (hex string)'
    })
    .option('suite', {
      alias: 's',
      type: 'string',
      default: 'OCRA-1:HOTP-SHA1-6:QN08',
      describe: 'OCRA suite string (default: "OCRA-1:HOTP-SHA1-6:QN08")'
    })
    .option('counter', {
      alias: 'c',
      type: 'string',
      default: '',
      describe: 'Counter value (hex string or decimal number)'
    })
    .option('question', {
      alias: 'q',
      type: 'string',
      default: '',
      describe: 'Challenge question (usually numeric string)'
    })
    .option('password', {
      alias: 'p',
      type: 'string',
      default: '',
      describe: 'Password or PIN'
    })
    .option('session', {
      alias: 'S',
      type: 'string',
      default: '',
      describe: 'Session information'
    })
    .option('timestamp', {
      alias: 't',
      type: 'string',
      default: '',
      describe: 'Timestamp value'
    })
    .option('digits', {
      alias: 'd',
      type: 'number',
      default: 6,
      describe: 'Number of digits in OTP'
    })
    .argv;

  try {
    let counterHex = argv.counter;
    if (counterHex && !counterHex.startsWith('0x') && /^\d+$/.test(counterHex)) {
      counterHex = BigInt(argv.counter).toString(16);
    }

    const otp = generateOCRA({
      suite: argv.suite,
      keyHex: argv.key,
      counter: counterHex,
      question: argv.question,
      password: argv.password,
      session: argv.session,
      timestamp: argv.timestamp,
      digits: argv.digits,
    });

    console.log(`✅ OCRA OTP (${argv.digits} digits):`, otp);
  } catch (err) {
    console.error('❌ OCRA generation failed:', err.message);
  }
}

console.log('🚀 Running OCRA generator CLI...');
main();