Encoding key, "Commando Group Daily Key Allocation List December 28 – January 3"

Until the end of the Second World War, British secret task forces such as the SOE and commando groups used double transposition encryption. This encryption list was valid from December 28, 1943 to January 3, 1944 and is one of a few surviving copies, seeing as the encryption lists had to be destroyed 48 hours after use.