CBC describes a block cipher mode. In cryptography, a block cipher mode of operation is an algorithm that uses a
block cipher to provide an information service such as confidentiality or authenticity. A block cipher by itself
is only suitable for the secure cryptographic transformation (encryption or decryption) of one fixed-length group of
bits called a block. A mode of operation describes how to repeatedly apply a cipher's single-block operation to
securely transform amounts of data larger than a block.