Im trying to install an rpm file on CentOS 5 and Im not sure how to resolve this issues it brings up:

$ rpm --install epel-release-6-5.noarch.rpm
warning: epel-release-6-5.noarch.rpm: Header V3 RSA/SHA256 signature: NOKEY, key ID 0608b895
error: Failed dependencies:
    rpmlib(FileDigests) <= 4.6.0-1 is needed by epel-release-6-5.noarch
    rpmlib(PayloadIsXz) <= 5.2-1 is needed by epel-release-6-5.noarch

What do the lines rpmlib(FileDigests) <= 4.6.0-1 mean? is rpmlib out of date or FileDigests out of date? Whats with the syntax of something followed by parentheses?

Ive tried to use yum so that it can resolve dependencies automatically but it is unable:

$ sudo yum --nogpgcheck install epel-release-6-5.noarch.rpm
...
Running rpm_check_debug
ERROR with rpm_check_debug vs depsolve:
rpmlib(FileDigests) is needed by epel-release-6-5.noarch
rpmlib(PayloadIsXz) is needed by epel-release-6-5.noarch
Complete!
(1, [u'Please report this error in https://bugzilla.redhat.com/enter_bug.cgi?product=Red%20Hat%20Enterprise%20Linux%205&component=yum'])

On this page https://bugzilla.redhat.com/show_bug.cgi?id=665073, they say my rpm is out of date but then say I should request an rpm file that works with my version of rpm (which is 4.4.2.3) but I don't want to do that. How do I make my system compatible with this rpm file?

Bonus points if you tell me how I can fix the public key error.