Cipher modes define the method in which data is encrypted. The stream cipher mode encodes data one bit at a time. The block cipher mode encodes data one block at a time. Although it tends to execute more slowly than stream cipher, block cipher is more secure. For more information on these modes, see Encrypting and Decrypting Data .
Initialization vectors are random numbers used as starting points when encoding data.
Usually, initialization vectors have the same number of bits as the block size and do not require encryption. With initialization vectors, two identical plaintext messages can be encoded with the same key and result in two completely different cipher messages. This variation is accomplished by encrypting each plaintext message with a different initialization vector. Salt values are most useful when, by using the same encryption key, large numbers of nearly identical packets are transmitted or stored. Typically, two identical packets encode as two identical cipher packets.