This cipher reel was captured by Union Forces at the
surrender of Mobile, Alabama in May 1865. It is an extremely
rare relic, being one of two known to have survived the American
Civil War. It bears in feint pencilled notations, the names of
the Confederate Signal Officer Captain Thomas Hawkings Clagett,
Jr., of Leesburg VA and several of his men.
As a trophy of war, , it was sent to the Chief Signal
Officer in Washington and later came into the hands of the
Signals Intelligence Service, forerunner of the National
Security Agency and the Army's Intelligence and Security
Command. The reel used a centuries of cipher known today as the
Vigenere. Poor security practices of Confederate users made a
potentially sophisticated cipher vulnerable to being read.