Nitro PDF Professional: Understanding encryption levels

Understanding encryption levels

While 128-bit keys are more secure, 40-bit encryption has been included for use with older PDF versions.

None. Prohibits all changes to the document.
Commenting, form filling and signing. Prohibits changes to the document, but allows for the addition of comments, form data, and digital signatures.
Page layout, form filling and signing. Allows the insertion, deletion and rotation of pages in addition to the addition of form data, and digital signatures.
Any except extracting pages. Allows all changes except for the extraction of pages.
Enable copying of text, images and other content, and access for the visually impaired.
Off. Prohibits readers selecting text or graphical objects, which would allow copying and pasting of content. In addition, it stops the textual content from being accessed by screen-reading software for the visually impaired.
On. Enables text and graphics selection, allowing for the extraction of this content. Also allows access text to be accessed by screen-reading software for the visually impaired.

None. Prohibits all changes to the document.
Inserting, deleting and rotating pages. Allows the insertion, deletion, and rotation of pages.
Form filling and digital signatures only. Prohibits changes to the document, but allows the addition to the addition of form data, and digital signatures.
Commenting, form filling, and digital signatures. Allows for the addition of comments, form data, and digital signatures.
Any except extracting pages. Allows all changes except for the extraction of pages.

Off. Prohibits readers selecting text or graphical objects, which would allow copying and pasting of content.
On. Enables text and graphics selection, allowing for the extraction of this content.

Enabled (cannot be disabled). Allows text to be accessed by screen-reading software for the visually impaired.