...

Compare with SSL (works out-of-the-box in 99.999% cases, and allows both, full and hard security with root certificates etc, or simple security based on _ok, I trust you first time, then we can work_.

If I'm on the same shared medium as you I can kill your SSL session with one packet.

Only if shared medium = vanilla CSMA/CD Ethernet or the like. Just because 'transport' is shared, doesn't mean you as the consumer of information carried by the network have visibility. ***** "The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from all computers." 118