Stream Cipher
A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream (keystream) to produce ciphertext, typically operating on bits or bytes one at a time. It is designed for efficient encryption of data streams, such as in real-time communications or large files, by generating a keystream that is XORed with the plaintext. Unlike block ciphers, stream ciphers do not require padding and can handle data of arbitrary length without fixed block sizes.
Developers should learn stream ciphers when implementing lightweight, high-speed encryption for scenarios like secure network protocols (e.g., TLS/SSL), wireless communications (e.g., GSM), or disk encryption, where low latency and minimal resource usage are critical. They are particularly useful in embedded systems or IoT devices due to their simplicity and efficiency, but require careful management of keystreams to avoid vulnerabilities like key reuse.