From b8bdef0ad12883d72ced5eb443e6e34a93bbbb91 Mon Sep 17 00:00:00 2001 From: Jay Berkenbilt Date: Sun, 25 Oct 2015 11:09:25 -0400 Subject: Implement deterministic ID For non-encrypted files, determinstic ID generation uses file contents instead of timestamp and file name. At a small runtime cost, this enables generation of the same /ID if the same inputs are converted in the same way multiple times. --- manual/qpdf-manual.xml | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) (limited to 'manual/qpdf-manual.xml') diff --git a/manual/qpdf-manual.xml b/manual/qpdf-manual.xml index 3174e68a..093d5b5b 100644 --- a/manual/qpdf-manual.xml +++ b/manual/qpdf-manual.xml @@ -990,12 +990,31 @@ outfile.pdf When any of the options in this section are specified, no output file should be given. The following options are available: + + + + + Causes generation of a deterministic value for /ID. This + prevents use of timestamp and output file name information in + the /ID generation. Instead, at some slight additional runtime + cost, the /ID field is generated to include a digest of the + significant parts of the content of the output PDF file. This + means that a given qpdf operation should generate the same /ID + each time it is run, which can be useful when caching results + or for generation of some test data. Use of this flag is not + compatible with creation of encrypted files. + + + - Causes generation of a fixed value for /ID. This is intended - for testing only. Never use it for production files. + Causes generation of a fixed value for /ID. This is intended + for testing only. Never use it for production files. If you + are trying to get the same /ID each time for a given file and + you are not generating encrypted files, consider using the + option. -- cgit v1.2.3-54-g00ecf