If you are looking for some tool to manage X.509 certificates then probably xca is your best guess. This is  a graphical tool and you can open any file and view the keys in it.

So, first install it:

sudo yum install xca

And some information on xca::

Description :   X Certificate and Key management is a graphic interface for managing

asymmetric keys like RSA or DSA, certificates and revocation lists. It is

intended as a small CA for creation and signing certificates. It uses the

OpenSSL library for the cryptographic operations.
:   Certificate signing requests (PKCS#10), certificates (X509v3), the signing

of requests, the creation of self-signed certificates, certificate revocation

lists and SmartCards are supported. For an easy company-wide use, customizable

templates can be used for certificate and request generation. The PKI structures

can be imported and exported in several formats like PKCS#7, PKCS#12, PEM,

DER, PKCS#8. All cryptographic data are stored in a byte order agnostic file

format, portable across operating systems.

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