DEC 5.1 wie benutzen?

[delphin06]

ich hab mir mal das filecrypt beispiel angeguckt von jus.

Jez hab ich versucht das n bisschen abzuändern, dass anstatt einer Datei direkt ein Stream verwendet wird. Aber irgendiwe klappt das nich. Da kommt dann ein Fehler mit der Meldung "Stream-Lesefehler" und der tritt in der procedure:

Delphi-Quellcode:

procedure TDECCipher.EncodeStream(const Source, Dest: TStream; const DataSize: Int64; const Progress: IDECProgress);
begin
  DoCodeStream(Source, Dest, DataSize, Context.BlockSize, Encode, Progress);
end;

auf.

Hier mal meine abgeänderte version:

Delphi-Quellcode:

procedure EncodeMStream(const ADestFilename: String; const APassword: Binary;
                       ACipher: TDECCipherClass = nil; AMode: TCipherMode = cmCTSx;
                       AHash: TDECHashClass = nil);
 var
  Dest: TStream;

  procedure Write(const Value; Size: Integer);
  begin
    Dest.WriteBuffer(Value, Size);
  end;

  procedure WriteByte(Value: Byte);
  begin
    Write(Value, SizeOf(Value));
  end;

  procedure WriteLong(Value: LongWord);
  begin
    Value := SwapLong(Value);
    Write(Value, SizeOf(Value));
  end;

  procedure WriteBinary(const Value: Binary);
  begin
    WriteByte(Length(Value));
    Write(Value[1], Length(Value));
  end;

var
  Sourcestr: TMemoryStream;
  Seed: Binary;
begin
  {if ASourceFileName=ADestFilename then
  begin
    showmessage('Source file and destination file must not be equal!');
    exit;
  end; }
  ACipher := ValidCipher(ACipher);
  AHash := ValidHash(AHash);
  Seed := RandomBinary(16);
  //Source := TFileStream.Create(ASourceFileName, fmOpenReadWrite);
  Sourcestr:=TMemorystream.Create();
  try
    sourcestr.WriteComponent(Form1.listview1);
    Dest := TFileStream.Create(ADestFilename, fmCreate);
    try
      with ACipher.Create do
        try
          Mode := AMode;
          Init(AHash.KDFx(APassword, Seed, Context.KeySize));

          WriteLong(Identity);
          WriteByte(Byte(Mode));
          WriteLong(AHash.Identity);
          WriteBinary(Seed);
          WriteLong(Sourcestr.Size);
          EncodeStream(Sourcestr, Dest, Sourcestr.Size);
          WriteBinary(CalcMAC);
        finally
          Free;
        end;
    finally
      Dest.Free;
    end;
      //ProtectStream(Source);
  finally
    Sourcestr.Free;
  end;
  //DeleteFile(AFileName);
end;

Was habe ich falsch gemacht?