Encryption Decryption Question:

Due to shortcomings in OFB mode Diffie has proposed an additional mode of operation, termed the counter mode. It differs from OFB mode in the way the successive data blocks are generated for subsequent encryptions. Instead of deriving one data block as the encryption of the previous data block, Diffie proposed encrypting the quantity i + IV (mod 264) for the ith data block, where IV is some initialization vector.