The byzantine packet format in PGP buys PGP nothing. There is no engineering reason for PGP to work that way, and PGP continues to suffer security issues because of it. I'm not arguing that PGP's original designers were incompetent, nor am I considering that argument, because it is totally uninteresting to me. What is relevant to me is the fact that today, that design is costly and bad. What more is there to think about? We should get rid of bad cryptography and replace it with good cryptography.