UDP and me
One project where my friend and officemate Steven T. Kent (now chief scientist and vice president at BBN, and a chief advisor to NSA) and I lost was our strong argument to put mandatory end-to-end encryption into TCPIt's interesting to read him saying this, because Reed is also one of the co-authors on this foundational paper on Internet design:http://web.mit.edu/Saltzer/www/publications/endtoend/endtoen...... and a straightforward consequence of the philosophy of the End To End Argument is that encryption doesn't belong in TCP at all --- different applications will have different service models, and E2E tells us not to confine those applications to a lowest common denominator provided by a low level protocol.At any rate, given the evolution of transport cryptography between 1980 and 2010, the lack of mandatory TCP encryption is almost certainly a mercy.