The
National Cryptologic Museum acquired this cipher device from
a West Virginian antique dealer, who found it in a home near Monticello.
Thomas Jefferson described a similar device for the English language in his writings,
and it is sometimes referred to as the "Jefferson Cipher Wheel." However,
the connection to Thomas Jefferson remains unproven. Jefferson's
design was probably based upon an unnamed earlier device. Similar
systems have been described by writers, including Francis Bacon in
1605, and may have been common among early European cipher bureaus
known as "Black Chambers."
The device uses scrambled alphabets on the edges of each wheel to cipher a message. By aligning the plain text letters in one row, any other row can be selected as the cipher text. The wheels are individually numbered and can be placed on the spindle in any prearranged order. The recipient of the cipher message arranges identical wheels in the same order, aligns the cipher letters in a row, and is able to read the plain text.
This particular artifact is thought to be the oldest extant true cipher device in the world. It was apparently for use with the French language, the world’s diplomatic language used through World War I.