>I want to use the _crypt.vcx to protect credit card numbers, social security numbers, etc. in an application that we distribute. We have and installed base of about 350 sites and have a routine that "audits" the users files and brings them up to date for the current version, no matter what their prior version is. My question is: I need to check certain fields in a dbf file and see if the data has been encrypted or not. If it is already encrypted, then I don't need to run the procedure to encrypt it. Is there a simple test that will return true or false depending on if the data is encrypted or not?

The problem is that in theory, an encrypted version may have the same character set than the un-encrypted data. I don't think there is a SIMPLE test; you might test whether the data contains specific characters only, but that test will not be very reliable.

I would strongly suggest that you have some marker stored somewhere, that indicates the version. For instance, you might use a different fieldname for the encrypted data.