Tuesday, December 11, 2012

document security

Lately I need to encrypt a few pdf and zip them securely. Have looked into and enjoyed using pdftk tool in centos and zip tool. Here is the short memo how to use the tool. Remember to test it out yourself first to verify.

=====Practical Example of pdftk from man page ====

       Collate scanned pages
         pdftk A=even.pdf B=odd.pdf shuffle A B output collated.pdf
         or if odd.pdf is in reverse order:
         pdftk A=even.pdf B=odd.pdf shuffle A Bend-1 output collated.pdf

       Decrypt a PDF
         pdftk secured.pdf input_pw foopass output unsecured.pdf

       Encrypt a PDF using 128-bit strength (the default), withhold all permissions (the default)
         pdftk 1.pdf output 1.128.pdf owner_pw foopass

       Same as above, except password ’baz’ must also be used to open output PDF
         pdftk 1.pdf output 1.128.pdf owner_pw foo user_pw baz

       Same as above, except printing is allowed (once the PDF is open)
         pdftk 1.pdf output 1.128.pdf owner_pw foo user_pw baz allow printing

       Join in1.pdf and in2.pdf into a new PDF, out1.pdf
         pdftk in1.pdf in2.pdf cat output out1.pdf
         or (using handles):
         pdftk A=in1.pdf B=in2.pdf cat A B output out1.pdf
         or (using wildcards):
         pdftk *.pdf cat output combined.pdf

       Remove ’page 13’ from in1.pdf to create out1.pdf
         pdftk in.pdf cat 1-12 14-end output out1.pdf
         or:
         pdftk A=in1.pdf cat A1-12 A14-end output out1.pdf

       Apply 40-bit encryption to output, revoking all permissions (the default). Set the owner PW to ’foopass’.
         pdftk 1.pdf 2.pdf cat output 3.pdf encrypt_40bit owner_pw foopass

       Join two files, one of which requires the password ’foopass’. The output is not encrypted.
         pdftk A=secured.pdf 2.pdf input_pw A=foopass cat output 3.pdf

       Uncompress PDF page streams for editing the PDF in a text editor (e.g., vim, emacs)
         pdftk doc.pdf output doc.unc.pdf uncompress

       Repair a PDF’s corrupted XREF table and stream lengths, if possible
         pdftk broken.pdf output fixed.pdf

       Burst a single PDF document into pages and dump its data to doc_data.txt
         pdftk in.pdf burst

       Burst a single PDF document into encrypted pages. Allow low-quality printing
         pdftk in.pdf burst owner_pw foopass allow DegradedPrinting

       Write a report on PDF document metadata and bookmarks to report.txt
         pdftk in.pdf dump_data output report.txt

       Rotate the first PDF page to 90 degrees clockwise
         pdftk in.pdf cat 1E 2-end output out.pdf

       Rotate an entire PDF document to 180 degrees
         pdftk in.pdf cat 1-endS output out.pdf

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How to zip a folder containing file and encrypt the whole folder

example file folder:
myfiles/doc1.txt
myfiles/doc2.txt

cmd:
# zip -r output.zip myfiles -e
(then type in password when prompted)


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Credit Sources

http://linux.about.com/od/commands/a/blcmdl1_zipx.htm
http://linux.about.com/od/commands/l/blcmdl1_zip.htm
http://linuxpoison.blogspot.com/2010/07/merge-or-encrypt-decrypt-pdf-files.html