$ gpg --gen-key
gpg (GnuPG) 2.0.14; Copyright (C) 2009 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

gpg: keyring `/home/herwarth/.gnupg/secring.gpg' created
gpg: keyring `/home/herwarth/.gnupg/pubring.gpg' created
Please select what kind of key you want:
   (1) RSA and RSA (default)
   (2) DSA and Elgamal
   (3) DSA (sign only)
   (4) RSA (sign only)
Your selection? 1
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 
Requested keysize is 2048 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 
Key does not expire at all
Is this correct? (y/N) y

GnuPG needs to construct a user ID to identify your key.

Real name: Herwarth Heitmann
Email address: herwarth@helux.nl
Comment: 
You selected this USER-ID:
    "Herwarth Heitmann <herwarth@helux.nl>"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
You need a Passphrase to protect your secret key.

can't connect to `/home/herwarth/.gnupg/S.gpg-agent': No such file or directory
gpg-agent[20906]: directory `/home/herwarth/.gnupg/private-keys-v1.d' created
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
gpg: /home/herwarth/.gnupg/trustdb.gpg: trustdb created
gpg: key 979378E8 marked as ultimately trusted
public and secret key created and signed.

gpg: checking the trustdb
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
pub   2048R/979378E8 2014-03-26
      Key fingerprint = DEEC DC77 B760 2E2D DBF2  F301 10AF 22F0 9793 78E8
uid                  Herwarth Heitmann <herwarth@helux.nl>
sub   2048R/6A9C1E44 2014-03-26
$

$ gpg --export -a 'Herwarth Heitmann' > RPM-GPG-KEY-helux

rpm -q gpg-pubkey --qf '%{name}-%{version}-%{release} --> %{summary}\n'
gpg-pubkey-c105b9de-4e0fd3a3 --> gpg(CentOS-6 Key (CentOS 6 Official Signing Key) <centos-6-key@centos.org>)
gpg-pubkey-0608b895-4bd22942 --> gpg(EPEL (6) <epel@fedoraproject.org>)
gpg-pubkey-5568bbb2-4cb9de99 --> gpg(RPM Fusion nonfree repository for EL (6) <rpmfusion-buildsys@lists.rpmfusion.org>)
gpg-pubkey-baadae52-49beffa4 --> gpg(elrepo.org (RPM Signing Key for elrepo.org) <secure@elrepo.org>)
gpg-pubkey-b06eb1af-51752a64 --> gpg(Helux <info@helux.nl>)

Remove old key

# rpm -e --allmatches gpg-pubkey-b06eb1af-51752a64

Install new key

# rpm --import RPM-GPG-KEY-helux

Create some stuff to sign RPMs

$ cd ~
$ vi .rpmmacros

%_signature gpg
%_gpg_name Herwarth Heitmann