Setup and check security options (permissions)
Access permissions for PDF documents are set when you encrypt the document. Password encryption is described in the corresponding how-to article. Certificate-based encryption is described in the corresponding how-to article.
Security handler classes have Permissions property of type TElPDFPermissions, which controls document permissions. TElPDFPermissions class includes a set of boolean properties, which specify individual permissions. With password-based encryption Permissions property belongs to the TElPDFPasswordSecurityHandler class. With certificate-based encryption Permissions property belongs to TElPDFPublicKeyRecipientGroup class. TElPDFPublicKeySecurityHandler class, which provides certificate-based encryption, controls includes one or more recipient groups. Those recipient groups are accessed via RecipientGroups property of TElPDFPublicKeySecurityHandler class.
Once the document is decrypted, the application can do whatever it wants with permissions -- ignore them, change them etc.. It's application developer's choice whether to obey document permission settings.