Eufinger was an instructor at Starfleet Academy in the 2260s. In 2269, Piper took Eufinger's course in computer cryptography, during which Eufinger made clear that the new wave-maze technology developed by the Klingon Empire made it impossible for Starfleet to tie into Klingon transmissions. The following year, Piper would learn that this was not impossible when she saw Commander Spock doing it. (TOS novel: Battlestations!)