AES Decryption using CommonCrypto - some characters are missing

Question

{
  "order_id": 5,
  "no": "19000038",
  "id": 10,
  "name": "John Doe"
}

I encrypt above data using online AES encryption website which is: https://www.devglan.com/online-tools/aes-encryption-decryption

using CBC mode, 256 Key size and Base64 output text format. I copied playground by @/backslash-f on this link: AES encryption in swift

and below is how I write to decrypt the encrypted data:

let stringData = Data(base64Encoded: stringValue, options: .ignoreUnknownCharacters)

            do {
                let aes = try AES(keyString: key)

                let decryptedData: String = try aes.decrypt(stringData!)
                print("String decrypted:\t\t\t\(decryptedData)")
            }
            catch {
                print("Something went wrong: \(error)")
            }

the data successfully decrypted but there are missing characters. Below is the decrypted data (as printed in the code):

String decrypted:           ,

"order_no": "19000038",

"id": 10,

"name": "John Doe"

}

as you can see, the first curly bracket until the "order_id": 5 is missing. Do anyone knows why this happens and how to fix this?

Answer 1

Figured out the problem. It is padding problem. CommonCrypto set padding to pkcs7 by default and we cannot change it. Then I use CryptoSwift library and change the padding to noPadding, then it works like charms!