private void EncryptNoteBody(DBNote note)
{
// decrypt the per note key
var plaintext_key = note.EncryptedKey.DecryptWithKey (encryptionMasterKey, User.MasterKeySalt);
note.IsEncypted = true;
note.Text = User.EncryptString (plaintext_key.ToByteArray (), note.Text).ToHexString ();
}