Accessing user credentials

Pardon the post but I can't figure out how to do this
from the VBA info on security.

Can I pick up a person's user name and credentials to use
the for access to an Access program. I would prefer to
manage Access user names for my users and allow them to
be enter the program with no log on assuming their
credentials are in my list of allowed users. These are
teachers and I don't want them to have to do a separate
log on to keep the data secure.

Thanks,

paul