Stream cipher, stream cipher, is an encryption in which the information is continuously encrypted character by character or bit by bit. The characters of a data stream are linked to the encryption stream generated from the key in the key stream generator.
In stream ciphering, the characters of the plaintext are XORed with the encryption stream. The ciphertext is generated from this linkage. The encryption stream has the same length as the plaintext. The advantage of the stream cipher over the block cipher lies in the delay-free encryption and decryption and in the length of the documents.
During decryption, the ciphertext is in turn XORed with the encryption stream to produce the plaintext. In synchronous stream ciphers, the sender and the receiver generate the encryption stream synchronously. The stream cipher is used in the RC4 algorithm, among others.