Sowohl 1924 als auch 1953 nutzten britische Mount-Everest-Expeditionen Verschlüsselung, um die Heimat vertraulich über eine etwaige Erstbesteigung des höchsten Bergs der Welt zu informieren.

In 1924, British mountaineers George Mallory and Andrew Irvine died trying to be the first to climb Mount Everest. An encrypted telegram reported the drama to their homeland. A blog reader identified the codebook that was used, but there is still one word, the meaning of which is unknown.