Over the weekend, Mike Rousos (a BCL tester who's been temporarily drafted onto the security team) posted an interesting piece about the new BCL registry security support on the BCL blog.  While the title mentions RegistryPermission, the post is actually about the NT security features of the registry classes rather than CAS permissions.  Mike covers the difference between RegistryRights and RegistryPermissionCheck -- two features that are nice additions to the BCL registry support.  Worth checking out if you spend much time working with NT security on the registry.