[pdftex] ID string in final PDF vs. same PDF checksum for same inputs

[Quirin Scheitle]

Dear PdfTEX Developers,

I am currently trying to create PDFs with the same checksum for the same inputs.

Apparently [1, own tests] the “ID” string in the PDF avoids this.

Is there any way to, e.g., set this string to a constant value or leave it out?

Thank you, Kind regards
Quirin



[1] http://tex.stackexchange.com/questions/5401/how-to-prevent-different-checksums-for-different-typesets

[Akira Kakuto]

Post by Quirin Scheitle
I am currently trying to create PDFs with
the same checksum for the same inputs.

If you are using TeX Live 2016, try to set environment
variables like
SOURCE_DATE_EPOCH=1486439625
SOURCE_DATE_EPOCH_TEX_PRIMITIVES=1

The latter will be changed in TeX Live 2017 as
FORCE_SOURCE_DATE=1

Best,
Akira

[Karl Berry]

ID string in final PDF vs. same PDF checksum

In addition to Akira's reply, there is reference information about this
in the pdftex manual. "texdoc pdftex",
or, as linked from http://ctan.org/pkg/pdftex,
http://mirrors.ctan.org/systems/doc/pdftex/manual/pdftex-a.pdf

Hope this helps,
Karl

[Quirin Scheitle]

Thank you, Karl and Akira!

For the record, those 3 lines fix my PDF checksum problem:

\pdfinfoomitdate=1
\pdfsuppressptexinfo=-1
\pdftrailerid{static}

Kind regards
Quirin