All,

I am new to using iText and Adobe Acrobat.  I do not know the cause of an 
approval signature being reported as corrupted.  The same signing algorithm 
routine succeeds without a problem when performing certifications.  
Unfortunately, when trying to sign a visible signature field the signature is 
never reported as valid, whether signing a iText certified document that allows 
for comments, form fill-in, etc. or an uncertified PDF form.  The version of 
the form being signed is version 1.6.  It is not an XFA or XML PDF and is just 
a simple single page form.

I applied a signature manually using Acrobat 9 without any problems in contrast 
to the consistent failures applied using recommended iText routines.  I have 
provided the abbreviated signature dictionary details in this e-mail, here:

VALID SIGNATURE: Manually Signed signature dictionary object created using the 
same self-signed certificate reports no problems:
=== 
61 0 obj
<</ByteRange[0 122373 133007 2977 ]             /Contents< hashvalue 
>/Filter/Adobe.PPKLite/M(D:20100426083458-04'00')/Name(Applicant 
Notary)/Prop_Build<</App<</Name/Exchange-Pro/OS[/Win]/R 
590594/REx(9.3.2)/TrustedMode false>>/Filter<</Date(Apr  3 2010 
00:00:00)/Name/Adobe.PPKLite/R 131103/V 2>>/PubSec<</Date(Apr  3 2010 
00:00:00)/NonEFontNoWarn true/R 131103>>>>/Reason(Test Manual Sign of Version 
1.6 PDF)/Reference[<</Data 5 0 R/DigestLocation[133444 34 ]           
/DigestMethod/MD5/DigestValue<d81984d597c7b4e3cf48b672dff1e03e>/TransformMethod/FieldMDP/TransformParams
 62 0 R/Type/SigRef>>]/SubFilter/adbe.pkcs7.detached/Type/Sig>>
endobj
62 0 obj
<</Action/All/Type/TransformParams/V/1.2>>
endobj
...
trailer
<</ID 
[<d7854085cdf347d1e9f744dc09c6bbac><1c4f2be802f919517e88e704622d1ab9>]/Root 5 0 
R/Size 58/Info 57 0 R>>
startxref
108991
%%EOF
=== 

INVALID SIGNATURE: iText version of self-signed certificate's signature 
dictionary object reported as invalid, specifically:
- The Document has been altered or corrupted since the Signature was applied.
- The signer's identity was valid when it was issued, but no revocation checks 
could be made to validate the identity art this time.
=== 
78 0 obj
<</Filter/Adobe.PPKLite/Type/Sig/Cert(<cert_info>)/Reason(Applicant application 
signs to ensure any post-signature alterations are detected.)/R 65541/Contents 
< smaller_hash_value >/M(D:20100426185912-04'00')/Location(Jerkwater, 
U.S.A.)/Name(Applicant Notary)/SubFilter/adbe.x509.rsa_sha1/ByteRange [0 115798 
116320 8742 ]                                                         >>
endobj
=== 

I used Paulo Soares code snippet to perform the signing, which works fine for 
certification signatures for the same FDF PDF form 
(http://itextpdf.sourceforge.net/howtosign.html#howtosign). 

Could someone please inform me as to what I am doing wrong and the cause of the 
iText generated dictionary reporting corruption?

Mike


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