Encrypting a Document

To encrypt a document, the owner and user passwords must be given (here, fred and charles respectively):

A blank user password is common. In this event, PDF viewers will typically not prompt for a password for when opening the file or for operations allowable with the user password.

In addition, the usual method can be used to give the existing owner password, if the document is already encrypted.

When using AES encryption, the option is available to refrain from encrypting the metadata. Add -no-encrypt-metadata to the command line.