An apparatus for protecting signals, including a first electronic computing device, and a second electronic computing device, wherein the second electronic computing device has a checking device, wherein the first and second electronic computing devices are designed to receive one or more different signals from one another and/or to emit them to one another, wherein the checking device is designed to check signals received from the second electronic computing device for formal correctness and/or to check the plausibility of said signals and to transmit the signals to the first electronic computing device and/or to a bus for transmitting data on the basis of the plausibility check and/or the check for formal correctness, wherein the second electronic computing device is configured according to a higher safety integrity level than the first electronic computing device. A corresponding method and to the use of the apparatus in a vehicle is also disclosed.