CODEWITHSUNDEEP
pdfencodingmetadata
nxl4
nxl4

Reputation: 734

What Encoding is Used in this PDF Metadata?

I'm looking at the binary of Adobe's PDF Reference document, and I'm wondering encoding is being used in the values of the metadata here:

<<
/Producer <30B9883671A1867F59929DEDF9AF32BC0029CF5414D3744A3273BCA8E7319382EA151980>
/Subject <30BE953B76E0A2306F8F8FFBFCA67E9D1D6A8F17418D200C1B6EEE88E726DAC4CE3E2CC1>
/Creator <37A89B34768D93347889CEAFBEF3>
/Title <219EBC7941A5943A6F9E80FAF5EF7E8D1A60881E04A630452968F38B>
/Author <30BE953B76E0A1266E8F8BF4E3E317B71166880A4B9135583865>
/ModDate <35E0C86923F1C36E2FC2DEA0A1F56BEF5F39C25D14D373>
/CreationDate <35E0C86923F1C36E2CCCDFAEA1F36EE128>
>>

So far, I can't find anything in the documentation or the ISO standard about this, and this is the only PDF I've seen so far with encoded metadata values.

Any ideas?

Upvotes: 0

Views: 748

Answers (1)

Jongware
Jongware

Reputation: 22478

It is standard encoding but the text strings have been encrypted. See 3.5 Ecryption in that same reference guide.

When inspecting a PDF, you should always start with reading the trailer dictionary (see 3.4.4 File Trailer). In your document this contains an /Encrypt key:

<<
   /Size 31667
   /ID [<19574527ECBF00E3EC0373879833EEF6> <24EE9EDB7DE40DB862FDB4C5D3493585>]
   /Info 7 0 R
   /Root 1 0 R
   /Encrypt 31666 0 R
>>

which is "required if document is encrypted".

Upvotes: 2

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