By default RHEL packages are signed with the RH gpg key. Before start the yum installation verifies gpg key.
warning: rpmts_HdrFromFdno: Header V3 DSA/SHA1 Signature, key ID 6b8d79e6: NOKEY
Public key for a52dec-0.7.4-8.el6.rf.x86_64.rpm is not installed
There are two way solution to fixed this error one is install that key or skip the key check with --nogpgcheck option in yum
solution 1 :
You need to install the Repoforge GPG key:
Solution 2 :
Use --nogpgcheck for disable gpg signature checking