New Features in Windows Server 2003
Only a few Active Directory security features have changed in Windows Server 2003:
Additional permission sets were added for delegating administration of Resultant Set of Policies (RSoP) and for managing InetOrgPerson object classes for interoperability with Novell Directory Services (NDS) and Netscape Directory Services (the other NDS).
Effective permission calculator.
The ACL Editor has a new Effective Permissions calculator that greatly simplifies management of overlapping inherited rights in Active Directory.
Smart card support.
The RunAs command now supports smart card authentication. The shell-based implementation of RunAs also includes special protection against misbehaving applications.