Secret Spathi Cypher
The Secret Spathi Cypher is "Huffi-Muffi-Guffi". It is known by billions of Spathi who, according to their leaders, swear never to reveal it even when threatened with considerable pain. By giving this password, one can establish visual communication with the Spathi High Council. There are two sources for obtaining the Cypher: Fwiffo on Pluto (who reveals it without being threatened, and in fact tells The Captain the cypher as soon as communications are established), or the Melnorme traders.
It is interesting to note that the Spathi swear never to reveal the Cypher "even when threatened with considerable pain," as opposed to the common human threat of death. This is likely a result of their natural and cultural cowardice.