public void ApplyDrm()
{
if (EncryptionProvider == null)
{
throw new ArgumentNullException("EncryptionProvider");
}
if (Encrypted)
{
throw new Exception("EPUB is already encrypted");
}
if (!HasRights)
{
throw new Exception("No rights specified");
}
// encrypt all elements except directory names and exempt files (content.opf, toc.ncx, cover image, etc)
var entries = _archive.Entries
.Where(x => !string.IsNullOrEmpty(x.Name) &&
!DrmExemptParts.Contains(x.FullName)).ToList();
foreach (var entry in entries)
{
var data = GetArchiveEntryBytes(entry.FullName);
entry.Delete();
var newEntry = _archive.CreateEntry(entry.FullName);
using (var stream = newEntry.Open())
EncryptionProvider.EncryptToStream(data, stream);
}
_encrypted = true;
}