I hate to re-invent the wheel so I'm looking for an existing solution to create a simple authentication system for my application. I've experimented for a while with using CardSpace or OpenID inside the application but I can't convince management that these would be working solutions. Of course, I could just build a simple login dialog where username, domain and (hashed) password is stored inside a database table and I've done such a thing many times already. I hate this solution since I feel it's just a weak option. And I don't want to spend too much time trying to make the whole logon system as secure as possible, especially since I suspect that there should be existing solutions for this.
So, next to OpenID/OpenAuth and CardSpace, are there any other Authentication solutions that can be used from a Delphi/WIN32 application?
Right now, the application will be used by many customers. Most are single-user environments, although it's likely that some of those will start to have two to 5 users once this authentication system is added. But we want to support a customer who needs to allow about 500 different users on the same application. These are spread over about 100 offices but they all connect to the same SQL Server database. (MS Access right now, but we're making it possible for this user to use SQL Server instead.) To make matters even more interesting, the customer uses Citrix to centralize the user systems and the application has straight access to the SQL Server database. It's not an ideal setup but then again, the customer isn't really paying for this. We're just setting up a test environment. A proof-of-concept which the customer will test for us. Flaws will be solved later on. But right now I need quick solutions and one of them is a practical authentication system where I don't have to write a lot of code.