Software

Access has at least 3 security features to consider:
1. Database Password - simple password protection for opening the mdb file.
2. Workgroup Administrator - uses a workgroup file (system.mdw by default) to create users, put them in groups and give those groups limited rights. Password protect the Admin account, and logon from the web page using a limited account...
3. Encrypt - physically scramble the data as it written to disk, so low level utilities can't read data strings from the mdw.

I recommend doing 2 and 3. Even you Encrypt, I also recommend storing the data file in a folder/share that the web engine (ASP or whatever) can access, but that the end user cannot access via http, ftp or anything else. There are many utilities for recovering/hacking Access mdw files!

pwd the mdb and use components to communicate

http://support.microsoft.com/default.aspx?scid=%2Fsupport%2Faccess%2Fcontent%2Fsecfaq%2Easp