Stream Ciphers

What is Stream Cipher?

Stream ciphers are encryption methods that encrypt digital data bit by bit or byte by byte, producing an encrypted data stream. Unlike block ciphers, which encrypt data in fixed-length blocks, stream ciphers are well suited for real-time applications such as video streaming and online communication, where data delay and efficiency are critical factors.

The basic operation principle of a stream cipher encryption algorithm is quite straightforward. It consists of generating a key stream (or pseudo-random number series), which is then combined with the message at the bit level (often using XOR operation) to produce the encrypted message. The decoding process works in the same way: the encrypted message is XORed again with the same key stream to recover the original message.