Draft mechanism for associating two sockets as part of the same session.

This method of association begins with the client connecting to
the server over a SOCK_STREAM socket. The server generates a random
verification string of length MIK_VERS to be that client's token. The
client responds by sending that same string over its SOCK_DGRAM socket,
thus associating the two on the server end. The server finalizes the
connection be sending the client a packet of type MIK_SEAL.

This is vulnerable to MITM attacks. There is no way around that, as far
as I see. Without preshared secrets, there will always be a point at
which intercepting will be an opportunity to claim someone's identity,
or half of it (the second connection).

Realizations like the above lead me to reconsider the benefits of TCP
alongside UDP.