Our RPM packages are now signed, allowing you (and your package manager) to verify their integrity. We use the same key to sign both our Debian packages and our RPMs. To tell RPM about this key, run:
rpm --import http://overviewer.org/rpms/overviewer.gpg.asc
Note that people currently using our RPM repository will likely have to add this key to RPM before they will be able to verify and install the new packages.