I recommend you to allocate a fix size for the /Contents field, which
alway will be enough (for example 10k).
2005/10/28, Shivakumar B <[EMAIL PROTECTED]>:
>
> thankx for the information, one question, How to calculate the byte space
> for the exclusion?
>
> regards
> Sivakumar.B
>
>
>
> [EMAIL PROTECTED]
>
> 10/27/2005 09:18 PM
> ToShivakumar B/SP/DBAsia/[EMAIL PROTECTED]
> [EMAIL PROTECTED]
> SubjectRe: [iText-questions] Reg: Pdf Signature Clarifications
>
>
>
>
>
>
> Maybe I have mistaken, but I think you should change the following line:
> dic2.put(PdfName.CONTENTS, new
> PdfString(out).setHexWriting(false));
> to
> dic2.put(PdfName.CONTENTS, new
> PdfString(out).setHexWriting(true));
>
> Of course your 'out' pkcs7 data should be binary data in this case.
>
> Adobe expects to a hex string, but you put a normal string into the
> /Contents field.
>
> Explanation from the pdf reference:
> "String objects can be written in two ways:
> • As a sequence of literal characters enclosed in parentheses ( ); see
> "Literal
> Strings,"
> • As hexadecimal data enclosed in angle brackets < >; see "Hexadecimal
> Strings""
>
> "The signature value. When ByteRange is present, the value is a
> hexadecimal string (see "Hexadecimal Strings") representing the
> value of the byte range digest."
>
> Best Regards,
> Tamas
>
> 2005/10/27, Shivakumar B <[EMAIL PROTECTED]>:
> >
> > Hi,
> >
> > i am putting the code that i have executed below,
> >
> > try {
> > log("reading the input...");
> > PdfReader reader = new PdfReader(args[0]);
> > FileOutputStream fout = new
> > FileOutputStream(args[1]);
> > PdfStamper stp =
> PdfStamper.createSignature(reader,
> > fout, '\0');
> > Calendar now = Calendar.getInstance();
> > PdfSignatureAppearance sap =
> > stp.getSignatureAppearance();
> > log("creating visible signature ...");
> > sap.setVisibleSignature(new Rectangle(100, 100,
> 200,
> > 200), 1, null);
> > sap.setLayer2Text("This is some custom made
> > text.\n\nDate: some date");
> > log("creating the pdf dictionary to set the
> > flags...");
> > PdfDictionary dic = new PdfDictionary();
> > dic.put(PdfName.FT, PdfName.SIG);
> > dic.put(PdfName.FILTER, new
> PdfName("SAFE.PPKSF"));
> > dic.put(PdfName.SUBFILTER, new
> > PdfName("adbe.pkcs7.detached"));
> > dic.put(PdfName.M, new PdfDate(now));
> > log("setting the dictionary to the
> appearance...");
> > sap.setCryptoDictionary(dic);
> > HashMap exc = new HashMap();
> > int file_len = reader.getFileLength();
> > exc.put(PdfName.CONTENTS, new Integer(file_len));
> > log("preclosing the signature appearance");
> > sap.preClose(exc);
> > log("creating another dictionary object...");
> > PdfDictionary dic2 = new PdfDictionary();
> > byte sg[] = readFile("signature_pdf.p7s");
> > byte out[] = new byte[(file_len-2) / 2];
> > System.arraycopy(sg, 0, out, 0, sg.length);
> > dic2.put(PdfName.CONTENTS, new
> > PdfString(out).setHexWriting(false));
> > sap.close(dic2);
> > log("complete");
> > } catch (Exception e) {
> > log("exception is ..."+e);
> > }
> > regards
> > Sivakumar.B
> >
> >
> >
> > [EMAIL PROTECTED]
> >
> > 10/26/2005 07:28 PM
> > ToShivakumar B/SP/DBAsia/[EMAIL PROTECTED]
> > cc
> > [email protected]
> > SubjectRE: [iText-questions] Reg: Pdf Signature Clarifications
> >
> >
> >
> >
> >
> >
> >
> > Signatures require knowledge and if you don't understand what you are
> > doing you won't get far. Post a snippet of your code and I'll see if I
> > can correct it.
> >
> > > -----Original Message-----
> > > From: [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED] On
> > > Behalf Of Shivakumar B
> > > Sent: Wednesday, October 26, 2005 12:04 PM
> > > To: Paulo Soares
> > > Cc: [email protected]
> > > Subject: RE: [iText-questions] Reg: Pdf Signature Clarifications
> > >
> > >
> > > Hi Paulo,
> > > thankx for the tip, i've corrected the error & gave
> > > the exclusion range as the length of the original pdf file.
> > > Is that correct?
> > > While putting the signature into the pdf, i gave the
> > > following command.
> > >
> > > dic2.put(PdfName.CONTENTS, new
> > > PdfString(out).setHexWriting(false));
> > >
> > > when i open in Adobe, i get the following error,
> > >
> > > Error during signature verification.
> > >
> > > Signature contains incorrect, unrecognized,
> > > corrupted or suspicious data.
> > > Support Information: SigDict /Contents illegal data
> > >
> > > Is this something wrong with the code or should I use
> > > trusted certificates to sign the pdf and then verify?
> > >
> > >
> > > regards
> > > Sivakumar.B
> > >
> > >
> > >
> > >
> > > [EMAIL PROTECTED]
> > >
> > > 10/26/2005 06:17 PM To
> > > Shivakumar B/SP/DBAsia/[EMAIL PROTECTED],
> > > [email protected]
> > > cc
> > > Subject
> > > RE: [iText-questions] Reg: Pdf Signature Clarifications
> > >
> > >
> > >
> > >
> > >
> > >
> > > Several errors:
> > >
> > > - you can only sign a field at a time. The second field must be signed
> > > in append mode.
> > >
> > > - the content "out" must have the size of the (exclusion - 2) / 2
> > >
> > > > -----Original Message-----
> > > > From: [EMAIL PROTECTED]
> > > > [mailto:[EMAIL PROTECTED]
> On
> > > > Behalf Of Shivakumar B
> > > > Sent: Wednesday, October 26, 2005 8:13 AM
> > > > To: [email protected]
> > > > Subject: [iText-questions] Reg: Pdf Signature Clarifications
> > > >
> > > >
> > > > Hi,
> > > > I am trying to create a Blank Signature Field for an
> > > > existing pdf, later, I will fill it up with the actual
> > > > signature. The following are the steps done,
> > > >
> > > > 1. Used PdfStamper to read the existing pdf.
> > > > 2. Used PdfFormField to create the Blank Signature
> > > > Field. (Set the flags, added the annotation to the
> > > > PdfStamper, closed the PdfStamper)
> > > > 3. Signatures were generated outside.
> > > > 4. Putting back the signatures to the pdf. This step
> > > > is not quite clear to me.
> > > > These steps were followed as given in the
> > > > "howtosign.html" page with little modification.
> > > >
> > > > a) I read the pdf using the PdfReader,
> > > > created the PdfStamper using the createSignature() method.
> > > > b) Get the List of Acro Fields from the
> > > > PdfStamper and get the Blank Signature Field Names.
> > > > c) Created PdfSignatureAppearance from the
> > > > PdfStamper.
> > > > d) Created the PdfDictionary with the fields
> > > > given in the sample
> > > > (Is there any page which documents
> > > > the constants and what we have to use for which purpose...)
> > > > (How are we
> > > > allocating the space for the contents?)
> > > > e) Created a HashMap and called the
> > > > preClose()..The Code throws NullPointer Exception here.
> > > > f) Created another dictionary object, to
> > > > which the signatures were added.
> > > > (How do we calculate
> > > > the byte space for the contents?)
> > > >
> > > >
> > > > for your reference, the actual code is below,
> > > >
> > > > PdfStamper stp =
> > > > PdfStamper.createSignature(reader, fout, '\0');
> > > > AcroFields af = stp.getAcroFields();
> > > > HashMap af_fields = af.getFields();
> > > > Iterator iter = af_fields.keySet().iterator();
> > > > Object key1 = null;
> > > > while (iter.hasNext()) {
> > > > key1 = iter.next();
> > > > log("Acro Fields Key : "+key1+" Value
> > > > : "+af_fields.get(key1));
> > > > }
> > > > ArrayList names = af.getBlankSignatureNames();
> > > >
> > > > for (int k = 0; k < names.size(); ++k) {
> > > > String name = (String)names.get(k);
> > > > log("Signature name: " + name);
> > > > PdfSignatureAppearance sap =
> > > > stp.getSignatureAppearance();
> > > > log("creating the visible signature
> > > > with name...");
> > > > sap.setVisibleSignature(new
> > > > Rectangle(100,100,200,200), 1, name);
> > > > log("creating the pdf dictionary to
> > > > set the flags...");
> > > > PdfDictionary dic = new PdfDictionary();
> > > > dic.put(PdfName.FT, PdfName.SIG);
> > > > dic.put(PdfName.FILTER, new
> > > > PdfName("SAFE.PPKSF"));
> > > > dic.put(PdfName.SUBFILTER, new
> > > > PdfName("adbe.pkcs7.detached"));
> > > > dic.put(PdfName.NAME, new
> > > > PdfString(PdfPKCS7.getSubjectFields((X509Certificate)
> > > > chain[0]).getField("CN")));
> > > > log("setting the dictionary to the
> > > > appearance...");
> > > > sap.setCryptoDictionary(dic);
> > > > HashMap exc = new HashMap();
> > > > exc.put(PdfName.CONTENTS, new
> > > > Integer(0x2502));
> > > > log("preclosing the appearance");
> > > > sap.preClose(exc);
> > > > PdfDictionary dic2 = new PdfDictionary();
> > > > byte[] out = readFile("signature_pdf.p7s");
> > > > dic2.put(PdfName.CONTENTS, new
> > > > PdfString(out).setHexWriting(true));
> > > > sap.close(dic2);
> > > > }
> > > > stp.close();
> > > >
> > > > any suggestion or help..
> > > >
> > > >
> > > > regards
> > > > Sivakumar.B
> > > >
> > > >
> > >
> > >
> > >
> > >
> >
> >
> >
>
>
>
