Decrypt given data previously encoded with seed cipher algo. SEED is a block cipher developed by South Korea's KISA, designed to provide secure encryption with a 128-bit block size and 128-bit key. SEED was created as a national standard for encryption in South Korea, offering security suitable for government and financial systems. SEED is considered secure but has been largely replaced by more widely used ciphers such as AES. 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.