Butterfly key expansion (BKE) is a somewhat novel concept to create almost indefinitely new matching public and private keys independently of each other based on a seed (or caterpillar) key pair and a shared expansion function. Although this concept was invented for credential provisioning to Vehicle-to-Everything (V2X) communication devices (DOI:10.1109/VNC.2013.6737583) these characteristics makes it interesting for all low bandwidth, low computational power, low secure storage devices. The …