PyPDF2 returns empty PDF after copying

def EncryptPDFFiles(password, directory):
    pdfFiles = []
    success = 0

    # Get all PDF files from a directory
    for folderName, subFolders, fileNames in os.walk(directory):
        for fileName in fileNames:
            if (fileName.endswith(".pdf")):
                pdfFiles.append(os.path.join(folderName, fileName))
    print("%s PDF documents found." % str(len(pdfFiles)))

    # Create an encrypted version for each document
    for pdf in pdfFiles:
        # Copy old PDF into a new PDF object
        pdfFile = open(pdf,"rb")
        pdfReader = PyPDF2.PdfFileReader(pdfFile)
        pdfWriter = PyPDF2.PdfFileWriter()
        for pageNum in range(pdfReader.numPages):
            pdfWriter.addPage(pdfReader.getPage(pageNum))
        pdfFile.close()

        # Encrypt the new PDF and save it
        saveName = pdf.replace(".pdf",ENCRYPTION_TAG)
        pdfWriter.encrypt(password)
        newFile = open(saveName, "wb")
        pdfWriter.write(newFile)
        newFile.close()
        print("%s saved to: %s" % (pdf, saveName))


        # Verify the the encrypted PDF encrypted properly
        encryptedPdfFile = open(saveName,"rb")
        encryptedPdfReader = PyPDF2.PdfFileReader(encryptedPdfFile)
        canDecrypt = encryptedPdfReader.decrypt(password)
        encryptedPdfFile.close()
        if (canDecrypt):
            print("%s successfully encrypted." % (pdf))
            send2trash.send2trash(pdf)
            success += 1

    print("%s of %s successfully encrypted." % (str(success),str(len(pdfFiles))))

      

        
        
        
      

    

I follow along with Pythons Automate the Boring Stuff. I'm having trouble copying a PDF document, but as of now, every time I run the program, my copied PDF is all blank pages. My encrypted PDF has the correct number of pages, but they are all blank (no content on the pages). I have happened before, but have not been able to recreate. I tried to quit in my sleep before closing my files. I'm not sure if the best practice for opening and closing files is in Python. I am using Python3 for reference.