In the actual production environment I am not in control of the form design,
so cannot change it.
I don't mean to be stubborn, but, as long as if I complete the field with
Adobe Reader and save the document, it tells me that the signature is valid,
but changes were made since the last signature. It also shows me that I
changed one field. This seems the right behaviour.
When you say that modifying the XFA will cause the results, your refer to
the way that iText modifies the XFA or to the XFA and PDF
standards/specifications? Because, obviously, Adobe's implementation handles
this ok.
Therefore, after modifying only one field in the form, that isn't signed by
the first signature, I don't expect the signature to be invalid, but to say
that only that field has changed since the last signature.
Thank you.
2011/5/5 Leonard Rosenthol <lrose...@adobe.com>
> If you want to only sign the data – then use a data signature. If you sign
> the entire form, then modifying the XFA will cause the results you are
> obtaining.
>
>
>
> *From:* Cosmin Ciuraru [mailto:cosmin.ciur...@gmail.com]
> *Sent:* Thursday, May 05, 2011 1:11 AM
>
> *To:* Post all your questions about iText here
> *Subject:* Re: [iText-questions] iText fill XFA Form and Digital signing
>
>
>
> I compared the xdp of the file filled in with iText and the file filled in
> with Adobe Reader. There are two differences:
>
>
>
> With Adobe:
>
>
>
> <form xmlns="http://www.xfa.org/schema/xfa-form/2.8/";
> checksum="q2aZZ1c6RqxVGD3ZxOOFJIOhtN4=">
>
> <subform name="form1">
>
> <instanceManager name="_form"/>
>
> <subform name="form">
>
> <area name="Body">
>
> <field access="readOnly" name="EmployeeName">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="Address">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="StateProv">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="HomePhone">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="CellPhone">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="SignatureField1"/>
>
> </area>
>
> <field name="TextField1">
>
> <value override="1"/>
>
> </field>
>
> </subform>
>
> <pageSet>
>
> <pageArea name="Page1"/>
>
> </pageSet>
>
> </subform>
>
> </form>
>
>
>
> with iText:
>
>
>
> <form xmlns="http://www.xfa.org/schema/xfa-form/2.8/";
> checksum="G3x6fZ508XKDw1SpO6DvjRZ3aQE=">
>
> <subform name="form1">
>
> <instanceManager name="_form"/>
>
> <subform name="form">
>
> <area name="Body">
>
> <field access="readOnly" name="EmployeeName">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="Address">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="StateProv">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="HomePhone">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="CellPhone">
>
> <value override="1"/>
>
> </field>
>
> <field access="readOnly" name="SignatureField1"/>
>
> </area>
>
> </subform>
>
> <pageSet>
>
> <pageArea name="Page1"/>
>
> </pageSet>
>
> </subform>
>
> </form>
>
>
>
> Notice that the checksum of the form is different (because of the next
> change) and the Adobe form contains:
>
>
>
> <field name="TextField1">
>
> <value override="1"/>
>
> </field>
>
>
>
> which was added after I filled in this text field with Adobe. So, filling
> in a text field, alters both the data section and add that field to the form
> section.
>
>
>
> I searched XFA specs 2.8 for <form xmlns="
> http://www.xfa.org/schema/xfa-form/2.8/";>, I wanted to know how the
> checksum is calculated and whether is used to validate the signature in any
> way, but didn't find anything.
>
> I should have found something though, according to Leonard's answer to this
> post:
>
>
> http://www.mail-archive.com/itext-questions@lists.sourceforge.net/msg49070.html
>
>
>
> Any suggestions, please?
>
>
>
> Thank you.
>
>
>
> 2011/5/5 Cosmin Ciuraru <cosmin.ciur...@gmail.com>
>
> Hello,
>
>
>
> While using the methods in my first post, in order to fill the fourth field
> in my form, I noticed, by exctracting the entire XFA structure (with
> templates, datasets, etc.), that, my datasets part had the following
> structure:
>
>
>
> <xfa:datasets xmlns:xfa="http://www.xfa.org/schema/xfa-data/1.0/";>
>
> <xfa:data>
>
> <xfa:datasets>
>
> <xfa:data>
>
> <xfa:form>
>
> ...
>
>
>
> So, the datasets and data tags were doubled. This, I suspected to generate
> the error message in Acrobat Reader (dataModel does not have a method
> 'clone') and went on to fix it.
>
>
>
> The behaviour, as much as I can tell was due to two reason:
>
> 1. The xml file that I imported had identation
> (tf.setOutputProperty(OutputKeys.INDENT, "yes"))
>
> 2. I got the itext source code, went into the com.itextpdf.text.pdf
> package, class XfaForm, method public void fillXfaForm(Node node) and
> changed the line 1154 from data.replaceChild(domDocument.importNode(node,
> true), data.getFirstChild())
> to
> data.replaceChild(domDocument.importNode(node.getFirstChild().getFirstChild(),
> true), data.getFirstChild()).
>
> Though it may not be the best solution, it generates the xfa ok.
>
>
>
> So, after recompiling iText and running my tests again, Acrobat Reader
> doesn't display the error message anymore, but, the first signature, that of
> the user, becomes invalid. If I click the signature panel, it now shows the
> details and it says that I have modified all the fields in the form, thus
> invalidating the signature, although, I actually only modified field number
> four, which wasn't included in the collection of objects for the first
> signature.
>
>
>
> From what I read from XFA specs 3.1, I have this:
>
>
>
> "Unlike an XML digital signature, a PDF signature signs the XFA form
> exactly as it is currently expressed,
>
> rather than signing a normalized copy. This means that it is not possible
> to make even meaningless
>
> changes to the XFA form without voiding the signature. For example,
> changing a space to a tab in between
>
> an element tag and the following attribute name voids the signature, even
> though it does not change the
>
> meaning of the XML."
>
>
>
> So, if you could point out whether is it possible to modify a field in a
> xfa form, without invalidating the signature, that, obviously, wasn't
> applied to that field?
>
>
>
> Thank you!
>
>
>
>
>
>
>
> 2011/5/3 Leonard Rosenthol <lrose...@adobe.com>
>
> Then modifying the entire XFA data block after document signing is a bad
> thing…
>
>
>
> *From:* Cosmin Ciuraru [mailto:cosmin.ciur...@gmail.com]
> *Sent:* Tuesday, May 03, 2011 7:57 AM
> *To:* Post all your questions about iText here
> *Subject:* Re: [iText-questions] iText fill XFA Form and Digital signing
>
>
>
> According to this classification:
>
> * *
>
> *
> http://help.adobe.com/en_US/livecycle/9.0/designerHelp/index.htm?content=000628.html
> *
>
>
>
> I use document signatures. The users just click on the signature field to
> sign the document and send it to me afterwards. There is no submit/email
> button.
>
>
>
> Thank you!
>
>
>
>
>
>
>
>
> ------------------------------------------------------------------------------
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>
>
>
>
>
>
> ------------------------------------------------------------------------------
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> The most intuitive, comprehensive, and cost-effective network
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> acquisition cost and overall TCO of any competing solution.
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> _______________________________________________
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>
> iText(R) is a registered trademark of 1T3XT BVBA.
> Many questions posted to this list can (and will) be answered with a
> reference to the iText book: http://www.itextpdf.com/book/
> Please check the keywords list before you ask for examples:
> http://itextpdf.com/themes/keywords.php
>
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The most intuitive, comprehensive, and cost-effective network
management toolset available today. Delivers lowest initial
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_______________________________________________
iText-questions mailing list
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iText(R) is a registered trademark of 1T3XT BVBA.
Many questions posted to this list can (and will) be answered with a reference
to the iText book: http://www.itextpdf.com/book/
Please check the keywords list before you ask for examples:
http://itextpdf.com/themes/keywords.php
