X - Certificate and Key management
http://hohnstaedt.de/xca/

This application is intended for creating and managing X.509 certificates, certificate requests, RSA, DSA and EC private keys, Smartcards and CRLs.
Everything that is needed for a CA is implemented.

Features:

  * Start your own PKI and create all kinds of certificates, requests or CRLs
  * Import and export them in any format like PEM, DER, PKCS#7, PKCS#12
  * Use them for your IPsec, OpenVPN, HTTPs or any other certificate based setup
  * Manage your Smart-Cards via PKCS#11 interface
  * Export certificates and requests to a OpenSSL config file
  * Create Subject- and/or Extension- templates to ease issuing similar certs
  * Convert existing certificates or requests to templates
  * Get the broad support of x509v3 extensions as flexible as OpenSSL but user friendlier
  * Adapt the Columns to have your important information at a glance