&quot;encryption is to prevent eavesdropping and session hijacks by the third party [...] it is Really Important for stock exchanges&quot;<p>Stock (and other financial) exchanges are major users of UDP, but in general they do not encrypt it.<p>Exchanges give clients direct connections to their networks using dedicated Ethernet lines, one per
customer. This, combined with datacenter security, is what prevents eavesdropping and session
hijacking. They do not use UDP over the Internet at all.