private static byte[] GetByteRangeDigest(PdfDocument document, PdfPKCS7 pkcs7, PdfSignature signature, string digestAlg)
{
Org.BouncyCastle.Crypto.IDigest digest = Org.BouncyCastle.Security.DigestUtilities.GetDigest(digestAlg);
iText.Kernel.Pdf.PdfArray b = signature.GetByteRange();
iText.IO.Source.RandomAccessFileOrArray rf = document.GetReader().GetSafeFile();
Stream rg = null;
try
{
rg = new iText.IO.Source.RASInputStream(new iText.IO.Source.RandomAccessSourceFactory().CreateRanged(rf.CreateSourceView(), b.ToLongArray(
)));
byte[] buf = new byte[8192];
int rd;
while ((rd = rg.Read(buf, 0, buf.Length)) > 0)
{
digest.BlockUpdate(buf, 0, rd);
}
byte[] dig = new byte[digest.GetDigestSize()];
digest.DoFinal(dig, 0);
return(dig);
}
catch (Exception e)
{
throw new iText.Kernel.PdfException(e);
}
finally
{
try
{
if (rg != null)
{
rg.Dispose();
}
}
catch (System.IO.IOException e)
{
// this really shouldn't ever happen - the source view we use is based on a Safe view, which is a no-op anyway
throw new iText.Kernel.PdfException(e);
}
}
}
