>You could also use the record's surrogate primary key as the encryption key. (Or STR() or TRANSFORM() of it if it's an integer and you need a string.)
>
>Cheers,
>Rich.

Yes, it occurred to me to use the primary integer key of the record which contains the memo field. (The seed is an integer.) That won't change because I don't mess with my primary keys. I thought I would xor that field with something else in the record that won't change (like the creation datetime of the record) so the seed won't be too easy to guess.

But this still leaves the problem of protecting the source code and/or guarding against decompilation. Are you concerned about that?

Peter