A public key infrastructure (PKI) is a credential verification scheme based upon public/private key-pair cryptography. This paper explores the PKI story so far and then goes on to identify some of the problems that stand in the way of globalisation and truly successful commercial PKI interworking. Current solutions to these problems are explained, with their respective benefits and limitations, and a much broader picture is evolved to show the likely destiny of the PKI as it begins to become really useful and fit into a wider commercial security context.