Saturday, March 17, 2007

Anonymizing PDF

File this under 'late-night LaTeX griping':

Is there any way of stripping metadata from a PDF file ? I'm writing a referee report for a journal, and used PDFLaTeX to create the report. When I scan it in acroread, there's all kinds of meta data that could identify me.

Now pdftk is a useful package that can strip out some of the simple metadata like 'creator'. However, pdftex adds "Advanced" fields, and one of them is the full pathname of the original LaTeX file. If your filesystem (UNIX) is anything like mine, then a part of that pathname is the /<username>/ section, which in many instances is an almost unique identifier. This also happens with dvipdfm, which uses the gs backend to create the PDF file, and with ps2pdf. pdftk cannot strip out these fields, because it doesn't appear to see them.

I suspect that if I owned a copy of the very-not-free Acrobat, I could meddle around with this metadata. Obviously I could submit the review as a Postscript file, but in general I prefer to maintain PDF. Further this problem also occurs if I want to do due diligence when submitting to conferences with double blind review, and sometimes I don't have the option to use PS.

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