Encrypt given data using bf-cfb cipher algo. Blowfish in CFB (Cipher Feedback) mode. CFB mode allows encryption of smaller data units, making it suitable for stream-like encryption. Developed by Bruce Schneier in 1993 as part of Blowfish, CFB mode is an improvement to the original ECB mode, providing better security for variable-length data. Similar to CBC, Blowfish in CFB is secure, but the 64-bit block size limits its long-term effectiveness against modern attacks. Our encryption process prepends the IV string used during the encryption process in the encrypted data so that it can be used during decryption.