You could encrypt/decrypt each layer with Proc.Encrypt and Proc.Decrypt. For example:
// encrypt and save
var
  i: integer;
begin
  for i := 0 to ImageEnView1.LayersCount - 1 do
  begin
    ImageEnView1.LayersCurrent := i;
    ImageEnView1.Proc.Encrypt('secret', ieeaTEA2);
  end;
  ImageEnView1.LayersSaveToFile('test.dat');
end;
// load and decrypt
var
  i: integer;
begin
  ImageEnView1.LayersLoadFromFile('test.dat');
  for i := 0 to ImageEnView1.LayersCount - 1 do
  begin
    ImageEnView1.LayersCurrent := i;
    ImageEnView1.Proc.Decrypt('secret', ieeaTEA2);
  end;
end;