PKI schemes provide a critical foundation for applied cryptographic protocols. However, there are no rigorous security specifications for realistic PKI schemes, and therefore, no PKI schemes were proven secure. Cryptographic systems that use PKI are analyzed by adopting overly simplified models of PKI, often simply assuming securely-distributed public keys. This is problematic given the extensive reliance on PKI, the multiple failures of PKI systems, and the complexity of both proposed and deployed systems, which involve complex requirements and models.