How to prevent different checksums for different typesets

Question

If I consider a simple LaTeX document such as:

\documentclass[11pt]{article}
\begin{document}
Hello, World!
\end{document}

then if I typeset it multiple times I get a different checksum each time

$ pdflatex test
This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009)
 restricted \write18 enabled.
entering extended mode
...
Output written on test.pdf (1 page, 12592 bytes).
Transcript written on test.log.
$ cksum test.pdf
2770399004 12592 test.pdf
$ pdflatex test
This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009)
 restricted \write18 enabled.
entering extended mode
...
Output written on test.pdf (1 page, 12592 bytes).
Transcript written on test.log.
$ cksum test.pdf
1225641903 12592 test.pdf

The different checksum is due to three lines changing in the PDF file:

/CreationDate (D:20101115092454-05'00')
/ModDate (D:20101115092454-05'00')
...
/ID [<E52BBC1CEFDC95455342C233D35D790A> <E52BBC1CEFDC95455342C233D35D790A>] >>

This is also the case with more complicated LaTeX input. Is there a way to typeset LaTeX files that would avoid this issue, so that if typeset multiple times, the checksum of the PDF file stays the same?

Answer 1

I think that it is worth repeating the answer here. (Since this a is an exact copy from superuser, I should not get any rep for it...so I'm marking it CW):

You can change the contents of the pdf's Info dictionary using pdftex's \pdfinfo macro:

\def\fixedpdfdate{D:20100413000000+00’00’}
\pdfinfo{
    /CreationDate (\fixedpdfdate)
    /ModDate (\fixedpdfdate) }

Put this right at the beginning of the document: there's some risk that the dictionary gets written out in several chunks.