Secret PDF enforces DRM controls with AES, random encryption algorithms and
public key technology. We design this application to help those PDF owners who
would like to restrict their documents from being redistributed and opened by
unauthorized users.

It is known to all that it is quite unsafe to protect your PDF documents with
only open password and owner password, since they could be both cracked and
shared easily. What' more, so many free pdf password remover software there
could remove your protection and restrictions.

We use key technology to deal with the issue. User generates a local key in
his/her computer device and sent it to the owner. The owner produces a new key
based on the local key. The user could only open the PDF document with the
owner's public key in the authorized device (the computer the user generates
the local key). In other computers, the open request will be denied.

Our built-in PDF viewer could also restrict the readers from accessing
permissions. In current version, our viewer only allows users to read rather
than copying, editing, saving, converting and printing.