/// <summary>Signs the document using the detached mode, CMS or CAdES equivalent.</summary>
/// <remarks>
/// Signs the document using the detached mode, CMS or CAdES equivalent.
/// <br /><br />
/// NOTE: This method closes the underlying pdf document. This means, that current instance
/// of PdfSigner cannot be used after this method call.
/// </remarks>
/// <param name="externalSignature">the interface providing the actual signing</param>
/// <param name="chain">the certificate chain</param>
/// <param name="crlList">the CRL list</param>
/// <param name="ocspClient">the OCSP client</param>
/// <param name="tsaClient">the Timestamp client</param>
/// <param name="externalDigest">an implementation that provides the digest</param>
/// <param name="estimatedSize">the reserved size for the signature. It will be estimated if 0</param>
/// <param name="sigtype">Either Signature.CMS or Signature.CADES</param>
/// <exception cref="System.IO.IOException"/>
/// <exception cref="Org.BouncyCastle.Security.GeneralSecurityException"/>
public virtual void SignDetached(IExternalSignature externalSignature, X509Certificate[] chain, ICollection
<ICrlClient> crlList, IOcspClient ocspClient, ITSAClient tsaClient, int estimatedSize, PdfSigner.CryptoStandard
sigtype)
{
if (closed)
{
throw new PdfException(PdfException.ThisInstanceOfPdfSignerIsAlreadyClosed);
}
ICollection <byte[]> crlBytes = null;
int i = 0;
while (crlBytes == null && i < chain.Length)
{
crlBytes = ProcessCrl(chain[i++], crlList);
}
if (estimatedSize == 0)
{
estimatedSize = 8192;
if (crlBytes != null)
{
foreach (byte[] element in crlBytes)
{
estimatedSize += element.Length + 10;
}
}
if (ocspClient != null)
{
estimatedSize += 4192;
}
if (tsaClient != null)
{
estimatedSize += 4192;
}
}
PdfSignatureAppearance appearance = GetSignatureAppearance();
appearance.SetCertificate(chain[0]);
if (sigtype == PdfSigner.CryptoStandard.CADES)
{
AddDeveloperExtension(PdfDeveloperExtension.ESIC_1_7_EXTENSIONLEVEL2);
}
PdfSignature dic = new PdfSignature(PdfName.Adobe_PPKLite, sigtype == PdfSigner.CryptoStandard.CADES ? PdfName
.ETSI_CAdES_DETACHED : PdfName.Adbe_pkcs7_detached);
dic.SetReason(appearance.GetReason());
dic.SetLocation(appearance.GetLocation());
dic.SetSignatureCreator(appearance.GetSignatureCreator());
dic.SetContact(appearance.GetContact());
dic.SetDate(new PdfDate(GetSignDate()));
// time-stamp will over-rule this
cryptoDictionary = dic;
IDictionary <PdfName, int?> exc = new Dictionary <PdfName, int?>();
exc[PdfName.Contents] = estimatedSize * 2 + 2;
PreClose(exc);
String hashAlgorithm = externalSignature.GetHashAlgorithm();
PdfPKCS7 sgn = new PdfPKCS7((ICipherParameters)null, chain, hashAlgorithm, false);
Stream data = GetRangeStream();
byte[] hash = DigestAlgorithms.Digest(data, SignUtils.GetMessageDigest(hashAlgorithm));
byte[] ocsp = null;
if (chain.Length >= 2 && ocspClient != null)
{
ocsp = ocspClient.GetEncoded((X509Certificate)chain[0], (X509Certificate)chain[1], null);
}
byte[] sh = sgn.GetAuthenticatedAttributeBytes(hash, ocsp, crlBytes, sigtype);
byte[] extSignature = externalSignature.Sign(sh);
sgn.SetExternalDigest(extSignature, null, externalSignature.GetEncryptionAlgorithm());
byte[] encodedSig = sgn.GetEncodedPKCS7(hash, tsaClient, ocsp, crlBytes, sigtype);
if (estimatedSize < encodedSig.Length)
{
throw new System.IO.IOException("Not enough space");
}
byte[] paddedSig = new byte[estimatedSize];
System.Array.Copy(encodedSig, 0, paddedSig, 0, encodedSig.Length);
PdfDictionary dic2 = new PdfDictionary();
dic2.Put(PdfName.Contents, new PdfString(paddedSig).SetHexWriting(true));
Close(dic2);
closed = true;
}