Planning for Directory Services in Public Key Infrastructures
  In this paper we provide a guide for public key infrastructure designers and administrators when planning for directory services. We concentrate on the LDAP directories and how they can be used to successfully publish PKI information. We analyse their available mechanisms and propose a best practice guide for use in PKI. We then take a look into the German Signature Act and Ordinance and discuss their part as far as directories concerning. Finally, we translate those to the LDAP directories practices. 
V. Karatsiolis, M. Lippert, A. Wiesmaier