/// <summary>
/// Prepare the data needed for digital signature. Unfortunately
/// CAPICOM's client-side implementation both hashes **AND** signs
/// passed in data instead of signing data already hashed, so the
/// **entire** PDF content bytes are needed.
/// </summary>
/// <param name="pdfIn">PDF file contents</param>
/// <returns>
/// Base64 encoded PDF content bytes client will sign.
/// </returns>
public string PreSign(byte[] pdfIn)
{
byte[] pdfRawContent = null;
bool isOdd = true;
var timeStamp = DateTime.Now;
var pdfSignature = new PdfSignature(
PdfName.ADOBE_PPKLITE, PdfName.ADBE_PKCS7_DETACHED
);
pdfSignature.Date = new PdfDate(timeStamp);
var exclusionSizes = new Dictionary<PdfName, int>();
exclusionSizes.Add(PdfName.CONTENTS, EXCLUSION_BUFFER * 2 + 2);
PdfReader reader = null;
int? signedFields = null;
try
{
var cert = new WebCertificateReader().GetSigningCertificate();
do
{
++DataReadCount;
reader = new PdfReader(pdfIn);
_acroFieldsWorker = new AcroFieldsReader(reader.AcroFields);
signedFields = signedFields ?? _acroFieldsWorker.SignedFields();
_memoryStream = new MemoryStream();
var stamper = signedFields == 0
? PdfStamper.CreateSignature(reader, _memoryStream, '\0')
: PdfStamper.CreateSignature(reader, _memoryStream, '\0', null, true)
;
_signatureAppearance = stamper.SignatureAppearance;
InitSignatureField(stamper);
pdfSignature.Reason = Reason;
_signatureAppearance.Certificate = cert;
_signatureAppearance.SignDate = timeStamp;
_signatureAppearance.CryptoDictionary = pdfSignature;
_signatureAppearance.PreClose(exclusionSizes);
using (Stream sapStream = _signatureAppearance.GetRangeStream())
{
using (var ms = new MemoryStream())
{
sapStream.CopyTo(ms);
pdfRawContent = ms.ToArray();
}
// pdfRawContent = StreamHandler.ReadAllBytes(sapStream);
// fix CAPICOM's broken implemetation: signature
// invalid if sapStream.Length is **ODD**
if ((pdfRawContent.Length % 2) == 0)
{
isOdd = false;
}
else
{
Reason += "\0";
}
DataSize = sapStream.Length;
}
// sanity check
if (DataReadCount > 2) throw new InvalidOperationException("DataReadCount");
} while (isOdd);
}
catch { throw; }
finally
{
HttpContext.Current.Session[InstanceLookupKey] = this;
if (reader != null) { reader.Dispose(); }
}
return Convert.ToBase64String(pdfRawContent);
}
/// <summary>
/// Prepare the data needed for digital signature. Unfortunately
/// CAPICOM's client-side implementation both hashes **AND** signs
/// passed in data instead of signing data already hashed, so the
/// **entire** PDF content bytes are needed.
/// </summary>
/// <param name="pdfIn">PDF file contents</param>
/// <returns>
/// Base64 encoded PDF content bytes client will sign.
/// </returns>
public string PreSign(byte[] pdfIn)
{
byte[] pdfRawContent = null;
bool isOdd = true;
var timeStamp = DateTime.Now;
var pdfSignature = new PdfSignature(
PdfName.ADOBE_PPKLITE, PdfName.ADBE_PKCS7_DETACHED
);
pdfSignature.Date = new PdfDate(timeStamp);
var exclusionSizes = new Dictionary <PdfName, int>();
exclusionSizes.Add(PdfName.CONTENTS, EXCLUSION_BUFFER * 2 + 2);
PdfReader reader = null;
int? signedFields = null;
try
{
var cert = new WebCertificateReader().GetSigningCertificate();
do
{
++DataReadCount;
reader = new PdfReader(pdfIn);
_acroFieldsWorker = new AcroFieldsReader(reader.AcroFields);
signedFields = signedFields ?? _acroFieldsWorker.SignedFields();
_memoryStream = new MemoryStream();
var stamper = signedFields == 0
? PdfStamper.CreateSignature(reader, _memoryStream, '\0')
: PdfStamper.CreateSignature(reader, _memoryStream, '\0', null, true)
;
_signatureAppearance = stamper.SignatureAppearance;
InitSignatureField(stamper);
pdfSignature.Reason = Reason;
_signatureAppearance.Certificate = cert;
_signatureAppearance.SignDate = timeStamp;
_signatureAppearance.CryptoDictionary = pdfSignature;
_signatureAppearance.PreClose(exclusionSizes);
using (Stream sapStream = _signatureAppearance.GetRangeStream())
{
using (var ms = new MemoryStream())
{
sapStream.CopyTo(ms);
pdfRawContent = ms.ToArray();
}
// pdfRawContent = StreamHandler.ReadAllBytes(sapStream);
// fix CAPICOM's broken implemetation: signature
// invalid if sapStream.Length is **ODD**
if ((pdfRawContent.Length % 2) == 0)
{
isOdd = false;
}
else
{
// Reason += '\0';
Reason += " ";
}
DataSize = sapStream.Length;
}
// sanity check
if (DataReadCount > 200)
{
throw new InvalidOperationException("DataReadCount");
}
} while (isOdd);
}
catch { throw; }
finally
{
HttpContext.Current.Session[InstanceLookupKey] = this;
if (reader != null)
{
reader.Dispose();
}
}
return(Convert.ToBase64String(pdfRawContent));
}
