For those of you not currently on the centos-devel mailing list, we are looking to test signed repomd.xml files (repomd.xml.asc) for CentOS-6 and CentOS-7. If you are interested in signed metadata repos, please look at this post:
http://lists.centos.org/pipermail/centos-devel/2015-April/013210.html
Also, if you are willing to test / help with the solution for signed metadata, please join the centos-devel mailing list and correspond there:
http://lists.centos.org/mailman/listinfo/centos-devel
Thanks, Johnny Hughes