import os,PyPDF2
os.chdir(‘D:\\My Documents‘)
for folderName, subfolders, filenames in os.walk(‘D:\\My Documents‘):
  for file in filenames:
    if file.endswith(‘.pdf‘):
       pdfFile = open(file, ‘rb‘)
       pdfReader = PyPDF2.PdfFileReader(pdfFile)
       pdfWriter = PyPDF2.PdfFileWriter()
       for pageNum in range(pdfReader.numPages):
         pdfWriter.addPage(pdfReader.getPage(pageNum))
       pdfWriter.encrypt(‘123456‘)
       resultPdf = open(file +‘encrypted.pdf‘, ‘wb‘)
       pdfWriter.write(resultPdf)
       resultPdf.close()