The exclusive or operation – a logical function applied to binary bits, like AND, OR, and NOT – is a fundamental encryption technique. It is often used in stream ciphers, which are widely used in web browsers when connecting to secure web servers.
Whenever your browser establishes a “secure” connection to a web site, it encrypts the data. The encryption often takes place byte-by-byte, since the software can’t always predict how much data will be sent. This encryption style requires a stream cipher.