The cellular automaton generator (CAG), a random number generator based on the one-dimensional cellular automaton (CA), is presented. Three procedures of secure implementation using the CAG are proposed and discussed. Implementations are very efficient in a wide range of hardware and software scenarios. That includes the advanced application of internet of things (IoT) and cyber-physical systems, which are both needed for computationally efficient cryptographic primitives. Furthermore, the proposed primitive is inherently resistant against the side-channel attack (SCA), where many currently available ciphers, such as the advanced encryption standard (AES), require additional hardware or software effort to prevent the SCA line of attack.