Decrypt given data previously encoded with cast cipher algo. CAST is a family of symmetric block ciphers with variable key sizes, designed as a fast and secure encryption method. CAST was developed in the 1990s by Carlisle Adams and Stafford Tavares and has been used in various security protocols. CAST is considered secure but not as widely used as AES or Camellia in modern cryptographic applications. 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.