Encrypt given data using cast5-ecb cipher algo. CAST5 in ECB (Electronic Codebook) mode, where each block is encrypted independently, making it fast but less secure. CAST5 was introduced in the 1990s as an updated version of the CAST cipher, including ECB as one of its modes. CAST5-ECB is insecure due to the potential for repeating patterns in the ciphertext, and it is not recommended for use. Our encryption process prepends the IV string used during the encryption process in the encrypted data so that it can be used during decryption.