Last week we all found that in iOS 7 that the attachments that where being sent by the Mail app where not being encrypted. This could be some what of a problem for a lot of iOS users. So on rpetrich repo there is a yet again another patch to fix what Apple has missed.
So to protect your attachments in your email just add this repo to your Cydia sources, and install the free tweak Attachment Encryptor.

http://rpetri.ch/repo