/// <summary> /// Prepares an /// <see cref="PdfPKCS7"/> /// instance for the given signature. /// This method handles signature parsing and might throw an exception if /// signature is malformed. /// <p> /// The returned /// <see cref="PdfPKCS7"/> /// can be used to fetch additional info about the signature /// and also to perform integrity check of data signed by the given signature field. /// </p> /// Prepared /// <see cref="PdfPKCS7"/> /// instance calculates digest based on signature's /ByteRange entry. /// In order to check that /ByteRange is properly defined and given signature indeed covers the current PDF document /// revision please use /// <see cref="SignatureCoversWholeDocument(System.String)"/> /// method. /// </summary> /// <param name="signatureFieldName">the signature field name</param> /// <param name="securityProvider">the security provider or null for the default provider</param> /// <returns> /// a /// <see cref="PdfPKCS7"/> /// instance which can be used to fetch additional info about the signature /// and also to perform integrity check of data signed by the given signature field. /// </returns> public virtual PdfPKCS7 ReadSignatureData(String signatureFieldName) { PdfSignature signature = GetSignature(signatureFieldName); if (signature == null) { return(null); } try { PdfName sub = signature.GetSubFilter(); PdfString contents = signature.GetContents(); PdfPKCS7 pk = null; if (sub.Equals(PdfName.Adbe_x509_rsa_sha1)) { PdfString cert = signature.GetPdfObject().GetAsString(PdfName.Cert); if (cert == null) { cert = signature.GetPdfObject().GetAsArray(PdfName.Cert).GetAsString(0); } pk = new PdfPKCS7(PdfEncodings.ConvertToBytes(contents.GetValue(), null), cert.GetValueBytes()); } else { pk = new PdfPKCS7(PdfEncodings.ConvertToBytes(contents.GetValue(), null), sub); } UpdateByteRange(pk, signature); PdfString date = signature.GetDate(); if (date != null) { pk.SetSignDate(PdfDate.Decode(date.ToString())); } String signName = signature.GetName(); pk.SetSignName(signName); String reason = signature.GetReason(); if (reason != null) { pk.SetReason(reason); } String location = signature.GetLocation(); if (location != null) { pk.SetLocation(location); } return(pk); } catch (Exception e) { throw new PdfException(e); } }
/// <exception cref="Org.BouncyCastle.Security.SecurityUtilityException"/> /// <exception cref="System.IO.IOException"/> private PdfName GetSignatureHashKey(String signatureName) { PdfSignature sig = sgnUtil.GetSignature(signatureName); PdfString contents = sig.GetContents(); byte[] bc = PdfEncodings.ConvertToBytes(contents.GetValue(), null); byte[] bt = null; if (PdfName.ETSI_RFC3161.Equals(sig.GetSubFilter())) { Asn1InputStream din = new Asn1InputStream(new MemoryStream(bc)); Asn1Object pkcs = din.ReadObject(); bc = pkcs.GetEncoded(); } bt = HashBytesSha1(bc); return(new PdfName(ConvertToHex(bt))); }