Decrypt given data previously encoded with des-ofb cipher algo. DES in OFB (Output Feedback) mode, turning the block cipher into a stream cipher using a feedback mechanism. OFB mode was used to improve the flexibility of DES by enabling it to encrypt smaller blocks of data while minimizing error propagation. DES in OFB is still insecure due to the inherent weaknesses of the DES algorithm, especially the 56-bit key length. 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.