Decrypt given data previously encoded with aes256 cipher algo. AES with 256-bit key, a widely used encryption standard. Defined in the AES standard, preferred for high-security applications. Highly secure, widely used in government and commercial sectors. Our decryption process assumes the IV string is prepended in the encoded string during the encryption process. You can not decrypt and get the correct results if the IV or passphrase mismatch occurs between encryption and decryption process.