index.js

import _ from 'lodash';
export const b64Table = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

export function encrypt(key, data) {
  xorEncrypt = (key, data) => {
    return _.map(data, function (c, i) {
      return c.charCodeAt(0) ^ key.charCodeAt(Math.floor(i % key.length));
    });
  },

  b64Encode = (data) => {
    var o1, o2, o3, h1, h2, h3, h4, bits, r, i = 0,
      enc = '';
    if (!data) {
      return data;
    }

    do {
      o1 = data[i++];
      o2 = data[i++];
      o3 = data[i++];
      bits = o1 << 16 | o2 << 8 | o3;
      h1 = bits >> 18 & 0x3f;
      h2 = bits >> 12 & 0x3f;
      h3 = bits >> 6 & 0x3f;
      h4 = bits & 0x3f;
      enc += b64Table.charAt(h1) + b64Table.charAt(h2) + b64Table.charAt(h3) + b64Table.charAt(h4);
    } while (i < data.length);
    r = data.length % 3;
    return (r ? enc.slice(0, r - 3) : enc) + '==='.slice(r || 3);
  },

  data = this.xorEncrypt(key, data);
  return this.b64Encode(data);
}

export function decrypt(key, data) {
  b64Decode = (data) => {
      var o1, o2, o3, h1, h2, h3, h4, bits, i = 0,
          result = [];
      if (!data) {
        return data;
      }

      data += '';
      do {
        h1 = b64Table.indexOf(data.charAt(i++));
        h2 = b64Table.indexOf(data.charAt(i++));
        h3 = b64Table.indexOf(data.charAt(i++));
        h4 = b64Table.indexOf(data.charAt(i++));
        bits = h1 << 18 | h2 << 12 | h3 << 6 | h4;
        o1 = bits >> 16 & 0xff;
        o2 = bits >> 8 & 0xff;
        o3 = bits & 0xff;
        result.push(o1);
        if (h3 !== 64) {
          result.push(o2);
          if (h4 !== 64) {
            result.push(o3);
          }
        }
      } while (i < data.length);
      return result;
    },

  xorDecrypt = (key, data) => {
    return _.map(data, function (c, i) {
      return String.fromCharCode(c ^ key.charCodeAt(Math.floor(i % key.length)));
    }).join('');
  },

  data = this.b64Decode(data);
  return this.xorDecrypt(key, data);
}