Hi Lester,

> >>Does anybody have any examples of the use of BLOB filters for encryption
> >>and decryption?
> >>
> >>I'm looking at ways of emulating the MySQL encryption functions ;)
> >
> > I'm not sure what BLOB filters have to do with this...
> >
> > Unless you can convince me you can actually use a blob-filter
> > with simple SQL (like with the IBX or IBO components).
>
> It was my understanding that a Blob Filter would process the data as it
> is written into the Blob, compress it or encode it, and then uncompress
> or unencode when the blob is read out.
>
> This is supposed to be a way to make sensitive data more secure, so that
> without the filter, a copy of the database would be of little use.
>
> Have I got it wrong? Which is quite possible :)

Well, last year in Fulda, Paul did a talk on an example BLOB-filter -
however, it seems they can be used only in embedded SQL.

What it comes down to, is that you need to _ask_ for data in a specific
sub-type. Next, Firebird will use the BLOB filter to convert the data
from the stored format to the asked-for format. However, when using
plain SQL, you cannot do that.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server.
Upscene Productions
http://www.upscene.com