I would like to make the a field in the back-end of a database unchangeable
but keep the rest of the information modifiable. To simplify I don't mind
people using the backend in any way they want I just want to set a field
"Company Name" so that it is hard coded by me and cannot be changed. The
database I am writing depends heavily on reports that all use this field in
the heading (my security from unauthorized copies). I could put it in a
table or in a module hard coded. Is there a way to keep it unchangeable?
Currently there is no security (which I prefer) and the front-end is
distributated as an MDE.

Thanks,
Dave

"dave k" <(E-Mail Removed)> wrote in message
news:5938D947-4E73-496F-A4CD-(E-Mail Removed)...
>I would like to make the a field in the back-end of a database unchangeable
> but keep the rest of the information modifiable. To simplify I don't mind
> people using the backend in any way they want I just want to set a field
> "Company Name" so that it is hard coded by me and cannot be changed. The
> database I am writing depends heavily on reports that all use this field
> in
> the heading (my security from unauthorized copies). I could put it in a
> table or in a module hard coded. Is there a way to keep it unchangeable?
> Currently there is no security (which I prefer) and the front-end is
> distributated as an MDE.
>
User level security is object based (forms, tables, etc). I'm not aware of a
method to achieve your objective at field level. You could use a text box
on a form to do it but this would mean setting up security.

Regards,
Keith.
www.keithwilby.com

Hopping in here (cos I can not see the OP's post):

You could do it without securing the database, by having a table with
one record & two fields:

CompanyName
MagicValue

When you set the CompanyName field before you sent your database to
that company, you would also store the MagicValue field as, for
example, the MD5 hash of the company name.

Then, in your MDE database startup code, check that the MD5 hash of
CompanyName, is equal to the MagicValue.

If it isn't, you know they've changed the CompanyName. (Kaboom!)

The security of this method would depend on the secrecy of how you
calculated the MagicVaue. Perhaps you could permute a common hash
function in some way; eg. add 5, or change the middle digit to 0, or
somesuch.

IOW you need not prevent them from changing the name; you need only
detect when they have done so.

HTH,
TC

Thanks! That is a great idea (why didn't I think of that?)!

You are correct, detection of a change is just as good as blocking it.

Dave


"TC" wrote:

> Hopping in here (cos I can not see the OP's post):
>
> You could do it without securing the database, by having a table with
> one record & two fields:
>
> CompanyName
> MagicValue
>
> When you set the CompanyName field before you sent your database to
> that company, you would also store the MagicValue field as, for
> example, the MD5 hash of the company name.
>
> Then, in your MDE database startup code, check that the MD5 hash of
> CompanyName, is equal to the MagicValue.
>
> If it isn't, you know they've changed the CompanyName. (Kaboom!)
>
> The security of this method would depend on the secrecy of how you
> calculated the MagicVaue. Perhaps you could permute a common hash
> function in some way; eg. add 5, or change the middle digit to 0, or
> somesuch.
>
> IOW you need not prevent them from changing the name; you need only
> detect when they have done so.
>
> HTH,
> TC
>
>