Requesting node 102 may comprise a personal computer such as an IBM PS/2 personal computer or a workstation such as an IBM RISC System/6000 workstation, while authenticating node 104 may comprise a host computer such as one of the IBM System/390 series having an ES/9000 processor. (IBM, PS/2, RISC System 6000, System/390 and ES/9000 are trademarks of IBM Corporation.) Communications channel 106 ma