SS7's security model is basically the same as BGP. Peers assume they can trust one another. The cost for entry here in Canada is about $50,000. Pay that to t

SS7's security model is basically the same as BGP. Peers assume they can trust one another. The cost for entry here in Canada is about $50,000. Pay that to the incumbent telco and you can basically have an SS7 connection of your very own, and announce cell phone numbers to the rest of the world. Electronic Funds Transfer is similarly based on trust. I can withdraw funds from any bank account just by knowing the account number. The only incentive is that you don't want to lose your account, but once you've been through the process of setting things up, it's quite easy to see how the system could be gamed. Maybe someday we'll be able to trust the underlying protocols our lives are built on top of.