>Copy aa.cdx to aa1.cdx with windows explorer since cdx is not encrypted.
>
>A cdx can contain a *lot* of the content of indexed fields. It might pay to check out what the cdx looks like using modi file or similar. Anything interesting visible there? ;-)

Probably, but the intent in 1993 was to prevent change of sensitive data without spending too much CPU on encryption. Cryptor has proved to be almost unnoticeable and very solid.