1.1 Block cipher
A block cipher can operates on block of data. Block cipher
algorithms that permute N-bit block of plaintext data encrypted
any other [2]. In this algorithm breaks into block and perform
operation on each block independently. It uses blocks of 8 or 16
bytes long. Security of block cipher is basically depending upon
the encryption function. Software implementation of block
cipher runs faster than software implementation of stream
cipher. Error transmitting in one block generally does not affect
other block. The data contains in each block is encrypted
independently, using the same key, identical plaintext blocks
produce identical cipher text blocks. Suppose that plain text is
227 byte long and the cipher text you are using operates on 16-
byte blocks. Algorithm takes the first 16-bytes of data, encrypts
them using the key table. Algorithm provides 16-byte of cipher
text. After first block, algorithm takes next block. The key table
doesn’t change from block to block.