The following window shows a byte-by-byte comparison result. The two PDF documents are virtually the same, the same meta data, the same PDF version, and the same page size, however, different total page number and different file size.
Author, Title, Subject, Keyword, Creator, Producer, Creation Time, and Modified Time, are the eight editable attributes that a user can modify quickly and easily with the free PDF Info software.
PDF Version ranges from 1.1 to 1.7, and the PDF version of a PDF document can be either upgraded or downgraded with the help of PDF Version Converter software.
The encryption attribute can be modified by PDF Encrypt & Decrypt software. And the permissions at the bottom can be changed with the help of the software.
Security Methods
User Password
Master Password
Allow Printing
Allow Changing the PDF Document
Allow Content Copying or Extraction
Allow Authoring Comments and Form Fields
Allow Form Field Fill-in or Signing
Allow Content Accessibility
Allow Document Assembly