Hi
I have a pdf to sign and external signature.
When I send completed array bytes to sign, I get correct signature but when
I send hash of bytes I get a
"The document has been altered or corrupted since the Signature was applied"
My code is:
PdfReader reader = new PdfReader(thePDF);
FileOutputStream fout = new FileOutputStream(new
File("\\cert_prova_sig1.pdf"));
PdfStamper stp = PdfStamper.createSignature(reader, fout, '\0');
Calendar now = Calendar.getInstance();
PdfSignatureAppearance sap = stp.getSignatureAppearance();
System.out.println("creating visible signature ...");
String reason = "reason";
String location = "location";
sap.setReason(reason);
sap.setLocation(location);
sap.setVisibleSignature(new Rectangle(100, 100, 186, 130), 1, null);
StringBuffer buf = new StringBuffer();
buf.append("Signed by ").append(" *******").append('\n');
sap.setLayer2Text(buf.toString());
sap.setAcro6Layers(true);
PdfDictionary dic = new PdfDictionary();
dic.put(PdfName.TYPE, PdfName.SIG);
dic.put(PdfName.FILTER, PdfName.ADOBE_PPKLITE);
dic.put(PdfName.SUBFILTER, PdfName.ADBE_PKCS7_DETACHED);
dic.put(PdfName.M, new PdfDate(now));
dic.put(PdfName.REASON, new PdfString(reason));
dic.put(PdfName.LOCATION, new PdfString(location));
System.out.println("setting the dictionary to the appearance...");
sap.setCryptoDictionary(dic);
HashMap exc = new HashMap();
// Espai a reservar, depenent de la signatura...
Integer reservedSpace = new Integer(0x6502);
exc.put(PdfName.CONTENTS, reservedSpace);
System.out.println("preclosing the signature appearance");
sap.setExternalDigest(new byte[128], new byte[20], null);
sap.preClose(exc);
byte[] hashREal = MessageDigest.getInstance("SHA1",
"BC").digest((Utils.streamToByteArray(sap.getRangeStream())));
byte[] churroBytes =
(Utils.streamToByteArray(sap.getRangeStream()));
// if signed with sap.getRangeStream is ok
// byte[] signat = signerCaja.signDataDettached(churroBytes);
// but when I signed with hash, I get error in verifiy signature
byte[] signat = signerCaja.signDataDettached(hashREal);
assertNotNull(signat);
File resp = new File("\\signaturaPREDettached.p7s");
resp.delete();
new FileOutputStream(resp).getFD().sync();
resp.createNewFile();
FileUtils.writeByteArrayToFile(resp, signat);
byte sg[] = signat;
// byte sg[] = theSignature;
byte[] out = new byte[(reservedSpace.intValue() - 2) / 2];
System.out.println("Sg Length : " + sg.length + " Out Length : " +
out.length);
System.arraycopy(sg, 0, out, 0, sg.length);
PdfDictionary dic2 = new PdfDictionary();
dic2.put(PdfName.CONTENTS, new PdfString(out).setHexWriting(true));
sap.close(dic2);
System.out.println("complete");
--
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