How can I perform regex searches over secured PDFs?

I want to do regex searches over the Air Canada Timetable PDF file (available here). Unfortunately, the file is secured, and that seems to prevent many of the usual ways of doing regex searches over PDF files from working. For example, Agent Ransack can't search such files.

I tried a couple of ways to remove the security restrictions so that I could save the file as text (e.g., PDFUnlock), but none were successful.

Acrobat and Google Drive can search the file, so its content is clearly accessible. Unfortunately, neither support regex searches.

I'm looking for a solution that will work under Windows 7. Help?

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