Stream Ciphers


Stream ciphers

Stream ciphers encrypt the bits of information one at a time – operate on 1 bit (or sometimes 1 byte) of data at a time (encrypt data bit-by-bit). Stream ciphers are faster and smaller to implement than block ciphers, however, they have an important security gap. If the same key stream is used, certain types of attacks may cause the information to be revealed.
Stream Ciphers vs Block ciphers
Stream ciphers are faster and smaller to implement than block ciphers, however, they have an important security gap. If the same key stream is used, certain types of attacks may cause the information to be revealed.

The difference between block ciphers and stream ciphers?
A stream cipher consists of a state machine that outputs at each state transition one bit of information. This stream of output bits is commonly called the running key. The state machine is nothing more than a pseudo-random number generator.
Block ciphers encrypt information by breaking it down into blocks and encrypting data in each block. A block cipher encrypts data in fixed sized blocks (commonly of 64 bits).