c# - PDFsharp 1.50 beta 3: Empty owner password error when adding password to PDF -


i'm exploring pdfsharp library , having issues password protecting pdfs.

following example on website http://www.pdfsharp.com/pdfsharp/index.php?option=com_content&task=view&id=36&itemid=47,

here code

 try  {    string filename = "hi.pdf";    file.copy(path.combine("c:/user/ichigo/desktop", filename),    path.combine(directory.getcurrentdirectory(), filename), true);     pdfdocument document = pdfreader.open(filename, "some text");     pdfsecuritysettings securitysettings = document.securitysettings;     securitysettings.userpassword="user";    securitysettings.ownerpassword="owner";     securitysettings.permitaccessibilityextractcontent = false;    securitysettings.permitannotations = false;    securitysettings.permitassembledocument = false;    securitysettings.permitextractcontent = false;    securitysettings.permitformsfill = true;    securitysettings.permitfullqualityprint = false;    securitysettings.permitmodifydocument = true;    securitysettings.permitprint = false;     document.save(filename);  }  catch (exception e)   { throw new exception("something went wrong : " + e); }

whenever add code sets passwords:

securitysettings.userpassword="user"; securitysettings.ownerpassword="owner";

i system.nullreferenceexception: object reference not set instance of object. when reach line saves pdf

document.save(filename); i'm getting error messages

---- debug assertion failed ---- ---- assert short message ---- empty owner password. ---- assert long message ----     @ pdfsharp.pdf.security.pdfstandardsecurityhandler.prepareencryption() in c:\users\ichigo\downloads\pdfsharp-migradocfoundation-1_50-beta3b\pdfsharp\src\pdfsharp\pdf.security\pdfstandardsecurityhandler.cs:line 590    @ pdfsharp.pdf.pdfdocument.dosave(pdfwriter writer) in c:\users\ichigo\downloads\pdfsharp-migradocfoundation-1_50-beta3b\pdfsharp\src\pdfsharp\pdf\pdfdocument.cs:line 392    @ pdfsharp.pdf.pdfdocument.save(stream stream, boolean closestream) in c:\users\ichigo\downloads\pdfsharp-migradocfoundation-1_50-beta3b\pdfsharp\src\pdfsharp\pdf\pdfdocument.cs:line 325    @ pdfsharp.pdf.pdfdocument.save(stream stream) in c:\users\ichigo\downloads\pdfsharp-migradocfoundation-1_50-beta3b\pdfsharp\src\pdfsharp\pdf\pdfdocument.cs:line 352    @ pdfsharp.pdf.pdfdocument.save(string path) in c:\users\ichigo\downloads\pdfsharp-migradocfoundation-1_50-beta3b\pdfsharp\src\pdfsharp\pdf\pdfdocument.cs:line 258

why getting these errors?

edit- here's stack trace system.nullreferenceexception.

something went wrong : `system.nullreferenceexception: object reference not set instance of object.`       @ pdfsharp.pdf.security.pdfstandardsecurityhandler.sethashkey(pdfobjectid id)    @ pdfsharp.pdf.io.pdfwriter.writebeginobject(pdfobject obj)    @ pdfsharp.pdf.pdfdictionary.writeobject(pdfwriter writer)    @ pdfsharp.pdf.pdfpage.writeobject(pdfwriter writer)    @ pdfsharp.pdf.pdfdocument.dosave(pdfwriter writer)    @ pdfsharp.pdf.pdfdocument.save(stream stream, boolean closestream)    @ pdfsharp.pdf.pdfdocument.save(stream stream)    @ pdfsharp.pdf.pdfdocument.save(string path)

turns out there problem pdfsharp 1.50 beta 3. nothing wrong code.

for quick fix, can download pdfsharp source code , make following change:

in file "pdfdocument.cs" in method "void dosave(pdfwriter writer)" "// hack: remove xreftrailer" (around line 375) , change (7 new lines replace 2 old lines):

// hack: remove xreftrailer if (_trailer pdfcrossreferencestream) {     // hack^2: preserve securityhandler.     pdfstandardsecurityhandler securityhandler = _securitysettings.securityhandler;     _trailer = new pdftrailer((pdfcrossreferencestream) _trailer);     _trailer._securityhandler = securityhandler; }

disclaimer: tested hi.pdf , helloworld.pdf only. while hope new code never behave worse old version, there no guarantee.

future versions of pdfsharp, newer pdfsharp 1.50 beta 3, should not require patch.


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