/**
* Signs a document with a PAdES-LTV Timestamp. The document is closed at the end.
* @param sap the signature appearance
* @param tsa the timestamp generator
* @param signatureName the signature name or null to have a name generated
* automatically
* @throws Exception
*/
public static void Timestamp(PdfSignatureAppearance sap, ITSAClient tsa, String signatureName) {
int contentEstimated = tsa.GetTokenSizeEstimate();
sap.SetVisibleSignature(new Rectangle(0,0,0,0), 1, signatureName);
PdfSignature dic = new PdfSignature(PdfName.ADOBE_PPKLITE, PdfName.ETSI_RFC3161);
dic.Put(PdfName.TYPE, PdfName.DOCTIMESTAMP);
sap.CryptoDictionary = dic;
Dictionary<PdfName,int> exc = new Dictionary<PdfName,int>();
exc[PdfName.CONTENTS] = contentEstimated * 2 + 2;
sap.PreClose(exc);
Stream data = sap.RangeStream;
IDigest messageDigest = DigestUtilities.GetDigest(tsa.GetDigestAlgorithm());
byte[] buf = new byte[4096];
int n;
while ((n = data.Read(buf, 0, buf.Length)) > 0) {
messageDigest.BlockUpdate(buf, 0, n);
}
byte[] tsImprint = new byte[messageDigest.GetDigestSize()];
messageDigest.DoFinal(tsImprint, 0);
byte[] tsToken = tsa.GetTimeStampToken(tsImprint);
if (contentEstimated + 2 < tsToken.Length)
throw new Exception("Not enough space");
byte[] paddedSig = new byte[contentEstimated];
System.Array.Copy(tsToken, 0, paddedSig, 0, tsToken.Length);
PdfDictionary dic2 = new PdfDictionary();
dic2.Put(PdfName.CONTENTS, new PdfString(paddedSig).SetHexWriting(true));
sap.Close(dic2);
}
private static void SetSigCryptoFromX509(PdfSignatureAppearance sigAppearance, X509Certificate2 card, X509Certificate[] chain)
{
sigAppearance.SetCrypto(null, chain, null, PdfSignatureAppearance.WINCER_SIGNED);
var dic = new PdfSignature(PdfName.ADOBE_PPKMS, PdfName.ADBE_PKCS7_SHA1)
{
Date = new PdfDate(sigAppearance.SignDate),
Name = PdfPKCS7.GetSubjectFields(chain[0]).GetField("CN"),
Reason = sigAppearance.Reason,
Location = sigAppearance.Location
};
sigAppearance.CryptoDictionary = dic;
const int csize = 4000;
var exc = new Dictionary<PdfName, int> { { PdfName.CONTENTS, csize * 2 + 2 } };
sigAppearance.PreClose(exc);
HashAlgorithm sha = new SHA1CryptoServiceProvider();
var s = sigAppearance.RangeStream;
int read;
var buff = new byte[8192];
while ((read = s.Read(buff, 0, 8192)) > 0)
{
sha.TransformBlock(buff, 0, read, buff, 0);
}
sha.TransformFinalBlock(buff, 0, 0);
var pk = SignMsg(sha.Hash, card, false);
var outc = new byte[csize];
var dic2 = new PdfDictionary();
Array.Copy(pk, 0, outc, 0, pk.Length);
dic2.Put(PdfName.CONTENTS, new PdfString(outc).SetHexWriting(true));
sigAppearance.Close(dic2);
}
private void UpdatePdfDictionaryContents(PdfSignatureAppearance pdfSignatureAppearance, byte[] encodedSignature)
{
var pdfDictionary = new PdfDictionary();
var paddedSignature = new byte[SIGNATURE_ESTIMATED_SIZE];
Array.Copy(encodedSignature, 0, paddedSignature, 0, encodedSignature.Length);
pdfDictionary.Put(PdfName.CONTENTS, new PdfString(paddedSignature).SetHexWriting(true));
pdfSignatureAppearance.Close(pdfDictionary);
}
