Encrypt given data using bf-ofb cipher algo. Blowfish in OFB (Output Feedback) mode. OFB mode turns a block cipher into a synchronous stream cipher by using a feedback loop. Introduced as part of Blowfish's design by Bruce Schneier in 1993, OFB mode is one of the feedback modes designed to improve security over ECB. Considered more secure than ECB but less secure than CBC or CFB, as it still suffers from problems with key reuse and error propagation. Our encryption process prepends the IV string used during the encryption process in the encrypted data so that it can be used during decryption.