Baud is the number of signal symbols transmitted per second on a channel. A symbol is a change in the physical signal, such as a voltage level, tone, or phase state. Baud is not always the same as bit rate: one symbol can carry one bit or several bits, depending on the encoding.
In cyber security, baud matters wherever systems still use serial lines, modems, industrial controllers, radio links, or other low-speed interfaces. Attackers may target these paths because they are easy to overlook, poorly documented, or left with weak authentication and default settings. Defenders need to know the baud rate to configure terminals, loggers, and monitoring tools correctly, and to verify that backup or maintenance links still work. In a small legacy modem or embedded device, a mismatch in baud can look like a failure, while a hidden service port running at a slow rate can become an access path if it is not secured.