Symmetric key cryptography
The symmetric key cryptography is based on a secret key that is the same for both parties. The same key is used for both encryption and decryption. This is a problem compared to the public key cryptography, as it is required to exchange the secret keys securely by some means. If an eavesdropper gets hold of the key, the security of the system is defeated.
Symmetric key is much faster than a public key and is ideal when encrypting/decrypting large chunks of data. Security of a symmetric key algorithm is based on the length of the key.
Stream cipher
A stream cipher is a type of a symmetric key cryptography where each bit or byte of data is encrypted individually with a stream of random bits called a key stream. Usually, each bit or byte is XORed (Exclusive OR) with a key stream. The length of the key stream is the same as the length of data. The security of a stream cipher depends upon the randomness of the key stream. If the same key stream is used for encrypting multiple...
