void CreateEncrypt(PdfElement elem)
{
var cf = elem.Get <PdfElement>("CF");
if (cf != null)
{
var stdCf = cf.Get <PdfElement>("StdCF");
if (stdCf != null)
{
}
}
var pValue = elem.Get <PdfInteger>("P").Value;
var vValue = elem.Get <PdfInteger>("V").Value;
var rValue = elem.Get <PdfInteger>("R").Value;
var oValue = elem.Get <PdfString>("O").ToISOBytes();
var uValue = elem.Get <PdfString>("U").ToISOBytes();
var filter = elem.Get <PdfName>("Filter")?.Name;
EncryptAlg cryptoMode = EncryptAlg.STANDARD_ENCRYPTION_128;
switch (rValue)
{
case 4:
if (vValue != 4)
{
throw new PdfException($"Invalid encrypt. V={vValue}, P={vValue}");
}
var cfObj = elem.Get <PdfDictionary>("CF");
var stdCfObj = cfObj.Get <PdfDictionary>("StdCF");
if (stdCfObj != null)
{
if (stdCfObj.Get <PdfName>("CFM")?.Name == "V2")
{
cryptoMode = EncryptAlg.STANDARD_ENCRYPTION_128;
}
}
break;
default:
throw new NotImplementedException($"Decrypt value {rValue}");
}
_decryptor = new PdfEncryption();
_decryptor.SetCryptoMode(cryptoMode, 0);
if (filter == "Standard")
{
if (rValue != 5)
{
_decryptor.SetupByOwnerPassword(_documentId, uValue, oValue, pValue);
Int32 checkLen = (rValue == 3 || rValue == 4) ? 16 : 32;
if (!EqualsArray(uValue, _decryptor.UserKey, checkLen))
{
_decryptor.SetupByUserPassword(_documentId, oValue, pValue);
}
}
}
}
void ParseObjStream(PdfElement elem)
{
PdfStream stream = elem.Get <PdfStream>("_stream");
var ms = new MemoryStream(stream.Bytes);
using (var br = new BinaryReader(ms))
{
PdfReader rdr = PdfReader.Create(br);
foreach (var obj in rdr.ReadObjStream())
{
var name = $"{obj.Item1} 0";
if (obj.Item2 is PdfDictionary objDict)
{
AddObject(name, objDict);
}
}
}
}