Spread spectrum is a communication technique in which a signal is spread over a wide frequency band, making it more resistant to interference and jamming. This is achieved by modulating the signal with a spreading code that spreads the signal energy over a larger bandwidth. Spread spectrum is commonly used in military, satellite, and secure communication systems, as well as in wireless networking technologies such as Bluetooth and Wi-Fi. The key benefits of spread spectrum include increased security, robustness against interference, and the ability to support multiple users on the same frequency band without causing interference.