feat(new-tool): added otp generator

src/tools/otp-code-generator-and-validator/otp.service.ts

@@ -0,0 +1,139 @@
+import { enc, HmacSHA1 } from 'crypto-js';
+import _ from 'lodash';
+import { createToken } from '../token-generator/token-generator.service';
+
+export {
+  generateHOTP,
+  hexToBytes,
+  verifyHOTP,
+  generateTOTP,
+  verifyTOTP,
+  buildKeyUri,
+  generateSecret,
+  base32toHex,
+  getCounterFromTime,
+};
+
+function hexToBytes(hex: string) {
+  return (hex.match(/.{1,2}/g) ?? []).map((char) => parseInt(char, 16));
+}
+
+function computeHMACSha1(message: string, key: string) {
+  return HmacSHA1(enc.Hex.parse(message), enc.Hex.parse(base32toHex(key))).toString(enc.Hex);
+}
+
+function base32toHex(base32: string) {
+  const base32Chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
+
+  const bits = base32
+    .replace(/=+$/, '')
+    .split('')
+    .map((value) => base32Chars.indexOf(value).toString(2).padStart(5, '0'))
+    .join('');
+
+  const hex = (bits.match(/.{1,8}/g) ?? []).map((chunk) => parseInt(chunk, 2).toString(16).padStart(2, '0')).join('');
+
+  return hex;
+}
+
+function generateHOTP({ key, counter = 0 }: { key: string; counter?: number }) {
+  // Compute HMACdigest
+  const digest = computeHMACSha1(counter.toString(16).padStart(16, '0'), key);
+
+  // Get byte array
+  const bytes = hexToBytes(digest);
+
+  // Truncate
+  const offset = bytes[19] & 0xf;
+  const v =
+    ((bytes[offset] & 0x7f) << 24) |
+    ((bytes[offset + 1] & 0xff) << 16) |
+    ((bytes[offset + 2] & 0xff) << 8) |
+    (bytes[offset + 3] & 0xff);
+
+  const code = String(v % 1000000).padStart(6, '0');
+
+  return code;
+}
+
+function verifyHOTP({
+  token,
+  key,
+  window = 0,
+  counter = 0,
+}: {
+  token: string;
+  key: string;
+  window?: number;
+  counter?: number;
+}) {
+  for (let i = counter - window; i <= counter + window; ++i) {
+    if (generateHOTP({ key, counter: i }) === token) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+function getCounterFromTime({ now, timeStep }: { now: number; timeStep: number }) {
+  return Math.floor(now / 1000 / timeStep);
+}
+
+function generateTOTP({ key, now = Date.now(), timeStep = 30 }: { key: string; now?: number; timeStep?: number }) {
+  const counter = getCounterFromTime({ now, timeStep });
+
+  return generateHOTP({ key, counter });
+}
+
+function verifyTOTP({
+  key,
+  token,
+  window = 0,
+  now = Date.now(),
+  timeStep = 30,
+}: {
+  token: string;
+  key: string;
+  window?: number;
+  now?: number;
+  timeStep?: number;
+}) {
+  const counter = getCounterFromTime({ now, timeStep });
+
+  return verifyHOTP({ token, key, window, counter });
+}
+
+function buildKeyUri({
+  secret,
+  app = 'IT-Tools',
+  account = 'demo-user',
+  algorithm = 'SHA1',
+  digits = 6,
+  period = 30,
+}: {
+  secret: string;
+  app?: string;
+  account?: string;
+  algorithm?: string;
+  digits?: number;
+  period?: number;
+}) {
+  const params = {
+    issuer: app,
+    secret,
+    algorithm,
+    digits,
+    period,
+  };
+
+  const paramsString = _(params)
+    .map((value, key) => `${encodeURIComponent(key)}=${encodeURIComponent(value)}`)
+    .join('&');
+
+  return `otpauth://totp/${encodeURIComponent(app)}:${encodeURIComponent(account)}?${paramsString}`;
+}
+
+function generateSecret() {
+  return createToken({ length: 16, alphabet: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567' });
+}