SQL Server: Mixed mode security: Can a non AD user (a local user, remote client) have a trusted connection to SQL?

I have used SQL Server trusted connections for years. It works well when the client app is a domain user. Imagine this three server config: - dbserver - webserver - domain controller I now have a situation of a web app that can no longer run on as a domain user (long story). This is a problem because this app stores its db connection string in the registry. If I use SQL auth, the SQL password is in clear. Is it possible to ? IOW: Is it possible to add webserver\localuser to SQL server as a trusted user, or can SQL server only trust domain users?