Metadata in signature dictionary

"Petras Petkus" <[email protected]> Fri, 12 Aug 2016 14:41:18 +0300
Newsgroups gmane.comp.java.lib.itext.general
Organization UAB "Mit-Soft"
Message-ID <[email protected]>
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I have a question to PDF experts regarding placing metadata in signature
dictionary. 

 

Our national PDF-based electronic document specification defines metadata
which may be included into signature dictionary. ISO 32000-1 section "14.3.2
Metadata Streams" states, that "Metadata, both for an entire document and
for components within a document, may be stored in PDF streams called
metadata streams". Therefore as a component, signature dictionary may
contain metadata entry. Section "7.3.8 Stream Objects" states, that "All
streams shall be indirect objects", but this requirement clashes with the
requirement for signature dictionary entries in "12.8 Digital Signatures",
which states: "When a byte range digest is present, all values in the
signature dictionary shall be direct objects."

 

I looked at the earlier (2014) draft of ISO 32000-2 and those requirements
were not changed, probably this contradiction will remain unchanged in the
final version.

 

Does that mean that metadata stream may not be included in signature
dictionary?

 

Thank you in advance for any input.


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vlink=3Dpurple><div class=3DWordSection1><p class=3DMsoNormal><span =
lang=3DEN-US>I have a question to PDF experts regarding placing metadata =
in signature dictionary. <o:p></o:p></span></p><p =
class=3DMsoNormal><span lang=3DEN-US><o:p>&nbsp;</o:p></span></p><p =
class=3DMsoNormal><span lang=3DEN-US>Our national PDF-based electronic =
document specification defines metadata which may be included into =
signature dictionary. ISO 32000-1 section &#8220;14.3.2 Metadata =
Streams&#8221; states, that &#8220;Metadata, both for an entire document =
and for components within a document, may be stored in PDF streams =
called metadata streams&#8221;. Therefore as a component, signature =
dictionary may contain metadata entry. Section &#8220;7.3.8 Stream =
Objects&#8221; states, that &#8220;All streams shall be indirect =
objects&#8221;, but this requirement clashes with the requirement for =
signature dictionary entries in &#8220;12.8 Digital Signatures&#8221;, =
which states: &quot;When a byte range digest is present, all values in =
the signature dictionary shall be direct =
objects.&quot;<o:p></o:p></span></p><p class=3DMsoNormal><span =
lang=3DEN-US><o:p>&nbsp;</o:p></span></p><p class=3DMsoNormal><span =
lang=3DEN-US>I looked at the earlier (2014) draft of ISO 32000-2 and =
those requirements were not changed, probably this contradiction will =
remain unchanged in the final version.<o:p></o:p></span></p><p =
class=3DMsoNormal><span lang=3DEN-US><o:p>&nbsp;</o:p></span></p><p =
class=3DMsoNormal><span lang=3DEN-US>Does that mean that metadata stream =
may not be included in signature dictionary?</span><span lang=3DEN-US =
style=3D'font-size:10.0pt;mso-fareast-language:LT'><o:p></o:p></span></p>=
<p class=3DMsoNormal><span lang=3DEN-US><o:p>&nbsp;</o:p></span></p><p =
class=3DMsoNormal><span lang=3DEN-US>Thank you in advance for any =
input.<o:p></o:p></span></p></div></body></html>
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