问题
I have a very strange problem and I am not sure where the issue is. I am creating a PDF and not setting any security restrictions or a password. When I open the PDF in Adobe Reader DC and get the properties,it does show the Security Method as No Security. However, the Document Assembly and Page Extraction are set to Not Allowed.
The PDF was created from a Word document and I simply did a save as PDF, no other options.
回答1:
In General
Please be aware that the "Document Restrictions Summary" summarizes restrictions that arise from a number of factors, the following ones coming to my mind:
Restrictions applied in the course of encryption
When encrypting a PDF, permissions for a number of features can be restricted for a regular user. Thus, if the PDF is opened with the user password, these restrictions apply and are shown in the summary; if it is opened with the owner password, they don't apply.
These are the restrictions one usually thinks of when checking the document properties Security tab.
Restrictions applied in the course of signing (certification & approval)
When a PDF is digitally signed with an integrated signature, a number of features are automatically restricted, and some more features may be restricted depending on the MDP transforms and locks applied by the signatures. These restrictions also are shown in the summary.
Restrictions applied by the viewer software used
The viewer you use may restrict what you can do with a PDF, e.g. a number of features of the Acrobat Pro editions are not present in Adobe Reader or are present but by default disabled. These restrictions also appear in the summary.
These viewer related restrictions may even differ based on the kind of document you have. E.g. in Adobe Reader they differ between PDF documents carrying a XFA form definition and those that don't.
Restrictions changed by usage rights signatures (aka Reader Enabling)
There is a special kind of PDF signature (usage rights signatures) which can lift some restrictions caused by the viewer software. If a PDF contains such a valid usage rights signature, some usually disabled features of the viewer may be enabled, a fact which also reflects in the summary.
If a PDF contains a usage rights signature which has been invalidated, e.g. by disallowed changes to the document, not only those usually disabled features remain disabled but some more features may become disabled, which again shows in the summary.
There may be additional factors still...
In Your Case
The "Not Allowed" entries you see for your file in Adobe Reader DC are restrictions of the third type listed above, they are restrictions applied by the viewer software used. If you opened the file in a superior Acrobat edition, those entries would become "Allowed".
来源：https://stackoverflow.com/questions/65019727/security-method-is-no-security-but-page-extraction-and-document-assembly-is-not