Cryptography: Block Cipher and Modes of Operation

•In cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks, with unvarying transformation that is specified by a symmetric key.

•A block cipher algorithm is a basic building block for providing data security.

•To apply a block cipher in a variety of applications, five “modes of operations” are defined by NIST.

1. Electronic Codebook
2. Cipher Block Chaining
3. Cipher Feedback
4. Output Feedback
5. Counter