How to fix 'invalid ciphertext size' error in Javascript ? (aes)

I'm trying to decrypt data using a key and the AES-JS library. Whenever I put a 16 bytes key I get the following error:

Error: "invalid ciphertext size (must be 16 bytes)"

I already tried to change the key to non-16 bytes value but then I get this error:

Error: "invalid key size (must be 16, 24 or 32 bytes)"

Here is my code so far :

export const getEventBlockData = (cm, eventBlockData) => {
  const encryptedBlockBuf = Buffer.from(eventBlockData, 'base64');
  const aes = new aesjs.AES(aesjs.utils.utf8.toBytes('1111111111111111'));
  const decryptedBlockBuffer = new Buffer(aes.decrypt(encryptedBlockBuf));
};

The part that generates an error is the last line with aes.decrypt(...

NB : the cm var is supposed to be the key but for testing purposes i replaced it by a string "1111111111111111" and the eventBlockData is the buffer i'm trying to decrypt, he has the following form :

Event Block Data :{"type":"Buffer","data":[49,56,53,50,55,51,53,49,50,50,48,48,48,49,48,48,48,48,49]} cm-service.js:61
Encrypted Block buff :{"type":"Buffer","data":[49,56,53,50,55,51,53,49,50,50,48,48,48,49,48,48,48,48,49]}

Thanks for your time! :)

Solution

Actually the error says invalid ciphertext size (must be 16 bytes), so the problem is not with your key and changing the key length, like you said you did in your post, won't resolve the problem as it doesn't concern the key.

It's a common and known issue that concerns the length of plaintext in CBC and it occurs when you use a cipher text with length other than a multiple of 16 bytes.

To solve this you need to add a padding for your encrypted text, for further details you can read Why must all inputs to AES be multiples of 16?.