For use in a distributed system where a client computer is operable to communicate with a server computer and to receive a digital certificate associated with a remote external component, apparatus for securing a communications exchange between computers includes a hasher, responsive to the client computer receiving a digital certificate, for hashing data associated with the client computer and the server computer with data associated with the digital certificate to create a first message digest, and a first transmitter for transmitting the first message digest to the remote external component.