The ancient Norse 'jotunvillur' code, dating back to the 12th or 13th century, has been cracked by Norwegian runologist K Jonas Nordby of the University of Oslo. The key was an unassuming wooden stick, found at the the Bergen Wharf in Norway and covered with runes. (photo)
From the recent article:
As for the wharf discovery, two men, Sigurd and Lavrans, carved their names in code and in standard runes on the wooden stick. Nordby studied the stick. All runes have names, and the jötunvillur code works by exchanging the rune sign with the last sound in the rune's name, said ScienceNordic.