ADO.NET, COM+, nTier and Security

[tstephan]

In the past we have used the classic nTier design with COM+, SQL Server
and MFC. We are currently working on a new project with an opportunity
to use .NET, ADO.NET, etc. One of the areas where I don't find a clear
migration path is with security. In the classic method, the server
side tiers were installed under COM+ and run as a known user. SQL
Server then gave full access to this known user so ADO simply needed to
make standard calls (no user or password required). This of course
also allowed the holy grail of connection sharing across the data
access layer since the same user account was used to access data. All
roles were handled by COM+ and Windows Security at the business layer.
How would this be handled with ADO.NET? This is an intranet only
application and we plan on using WSE, ADO.NET, SQL Server 2000. How do
I securely access my data without embedding user names and passwords.
Naturally I want to continue to use connection sharing. I have been
considering running the WSE host application under a known user but
that seems a bit kludgy.

Thanks,
Todd