Cipher Modes
There are different cipher modes; most symmetric keys use a block cipher and can encrypt a large amount of data quicker than asymmetric encryption. Let's look at these in turn:
- Stream Cipher: A stream cipher is a method of encrypting text (to produce ciphertext) in which a cryptographic key and algorithm are applied to each binary digit in a data stream, one bit at a time. It is normally used by asymmetric encryption.
- Block Cipher: A block cipher is where a block of data is taken and then encrypted; for example, 128 bits of data may be encrypted at a time. This is the method used today as it is much faster than a stream cipher. It is used by symmetric encryption with the exception of RC4.
Stream versus Block Cipher Analogy
We have two teams of four people who have been tasked with unloading a five-ton lorry full of skittles and placing them in a room on the bottom floor of a building.
There are skittles in boxes and there are skittles...
