Salsa20 is a stream cipher designed by Daniel J. Bernstein in 2005. It is known for its speed and security, making it suitable for various applications, including encryption in software and hardware. Salsa20 operates on 64-byte blocks and uses a 256-bit key, providing a high level of security against cryptographic attacks. The cipher employs a simple and efficient algorithm that combines addition, XOR, and rotation operations. This design allows Salsa20 to achieve high performance on both general-purpose processors and specialized hardware. Its popularity has led to its inclusion in several cryptographic protocols and libraries, enhancing data security across different platforms.