Encrypt given data using cast5-cbc cipher algo. CAST5 in CBC mode, using a 128-bit key for encryption, and XOR'ing each plaintext block with the previous ciphertext block. CAST5 is an evolution of the original CAST cipher, designed in the 1990s and used in various cryptographic applications. CAST5 is considered secure, but with the growth of more robust ciphers like AES, it is seen as somewhat outdated. Our encryption process prepends the IV string used during the encryption process in the encrypted data so that it can be used during decryption.