Encryption Properties

The owner password

This password is sometimes also referred to as the author’s password. This password grants full access to the document. Not only can the document be opened and read, it also allows the document's security settings, access permissions, and passwords to be changed.

If the password contains characters that are not in the Windows ANSI encoding (Windows Code Page 1252), the output document's compliance level is automatically upgraded to PDF version 1.7. This is because older PDF versions do not support Unicode passwords.

The access permissions granted when opening the document

The operations granted in a PDF document are controlled using permission flags. In order to set permission flags, the PDF document must be encrypted and have an owner password.

The restricted permissions apply whenever the document is opened with a password other than the owner password. The owner password is required to initially set or later change the permission flags.

When opening an encrypted document, the access permissions for the document can be read using Permissions. Note that the permissions might be different from the "Document Restrictions Summary" displayed in Adobe Acrobat.

The user password

This password protects the document against unauthorized opening and reading.

If a PDF document is protected by a user password, it cannot be opened without a password. The user or, if set, owner password must be provided to open and read the document.

If a document is not protected by a user password, it can be opened by without a password, even if an owner password is set.

If the password contains characters that are not in the Windows ANSI encoding (Windows Code Page 1252), the output document's compliance level is automatically upgraded to PDF version 1.7. This is because older PDF versions do not support Unicode passwords.