stream cipher

This term refers to a specific class of symmetric encryption where the plaintext is processed as a continuous flow rather than in fixed-size blocks. It is characterized by the generation of a pseudorandom keystream that is combined with the plaintext, typically using a bitwise XOR operation, to produce the ciphertext.

In practical application, stream ciphers are often preferred over block ciphers in environments where data arrives in a continuous stream or where low latency is critical, such as in real-time audio or video communication. A primary security concern with stream ciphers is the danger of keystream reuse, which can allow an attacker to decrypt messages if the same key and initialization vector are used twice.