My CryptoJS encryption/decryption is not working

Viktor picture Viktor · Sep 25, 2012 · Viewed 37k times · Source

I have an array of JSON arrays whose values I am trying to encrypt with CryptoJS and then print for use in another file, where these values should be decrypted using a user-given passphrase.

But I am doing something wrong and I am getting "Uncaught Error: Malformed UTF-8 data" when decrypting the URL's.

encrypt.js:

var encrypted = CryptoJS.AES.encrypt(item[key], pass);
json[j] += encrypted.ciphertext.toString(CryptoJS.enc.Base64);

decrypt.js:

var decrypted = CryptoJS.AES.decrypt(item[key], pass);
html += '<a href="' + decrypted.toString(CryptoJS.enc.Utf8) + '" target="_blank" class="socialico ' + key + '">' + icons[key] + '</a>';

I followed this example... Help, pretty please?

Answer

Jeff M picture Jeff M · Sep 25, 2012

That error message usually means the data wasn't decrypted correctly, and the resulting plaintext bytes don't form valid UTF-8 characters.

A couple things to check:

  • First, make sure you're using the same password for both encryption and decryption. You may want to keep a hash of the correct password so that you can verify if the user gave the correct password before you use it for decryption.
  • Second, make sure that the value item[key] is a string before encrypting. CryptoJS can't encrypt JSON objects. You'll have to serialize it first.