A number of readers wrote in this morning that they were experiencing issues when updating Fedora Linux. 

You may receive the following error on the elfutils-libelf package:

Unable to verify elfutils-libelf-0.129-1.fc7.x86_64

Details:
Public key for elfutils-libelf-0.129-1.fc7.x86_64.rpm is not installed

Apparently seven other packages are affected, which have not been publicly identified. These packages do have been signed, but when they were moved from testing to update, remained signed with the incorrect "test" key. It may be prudent to hold off on non-critical updates for a short bit of time while the Fedora developers work to resolve this issue.