//Helpmethod to output the streams in the storage
//private void WriteDoc(CompoundDocument.StoragePart storagePart, string p)
//{
// foreach (var store in storagePart.SubStorage)
// {
// string sdir=p + store.Key.Replace((char)6,'x') + "\\";
// Directory.CreateDirectory(sdir);
// WriteDoc(store.Value, sdir);
// }
// foreach (var str in storagePart.DataStreams)
// {
// File.WriteAllBytes(p + str.Key.Replace((char)6, 'x') + ".bin", str.Value);
// }
//}
/// <summary>
/// Read the package from the OLE document and decrypt it using the supplied password
/// </summary>
/// <param name="stream">The memory stream. </param>
/// <param name="encryption">The encryption object from the Package</param>
/// <returns></returns>
internal MemoryStream DecryptPackage(MemoryStream stream, ExcelEncryption encryption)
{
//Create the lockBytes object.
CompoundDocument.ILockBytes lb = null;
try
{
lb = CompoundDocument.GetLockbyte(stream);
if (CompoundDocument.IsStorageILockBytes(lb) == 0)
{
var doc = new CompoundDocument(lb);
return(GetStreamFromPackage(doc, encryption));
}
else
{
Marshal.ReleaseComObject(lb);
throw (new InvalidDataException("The stream is not an valid/supported encrypted document."));
}
}
catch (Exception ex)
{
throw (ex);
}
finally
{
Marshal.ReleaseComObject(lb);
lb = null;
}
}
/// <summary>
/// Check the file is encrpyted.
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
public static bool IsEncrypted(Stream stream)
{
Stream encrStream = new MemoryStream();
CopyStream(stream, ref encrStream);
CompoundDocument.ILockBytes lb = (CompoundDocument.GetLockbyte((MemoryStream)encrStream));
if (CompoundDocument.IsStorageILockBytes(lb) == 0)
{
return(true);
}
return(false);
}
