User login and security

[Computermike]

I have created an ADP and it seems to working fine, but I have made no
previsions regarding a security framework.

Should user names and login be kept in Access or SQL Server? Should I
assign rights to my user's in SQL Server or is there an "App User" account
that access uses to connect with SQL.

Any comments or links to help me build a security framework would be
appreciated.

Mike