Wheatstone-Plett Cipher Device from Riverbank Labs

On 3 December the Acquistion Chairman completed the indefinite loan of a rare Wheatstone-Plett cipher device from Riverbank Labs, Geneva, Illinois. This specific device is an irregular polyalphabetic substitution system invented in the 1860s by Sir Charles Wheatstone, and improved upon by J. St.Vincent Plett sometime thereafter. The British, French and Americans all tested the device and none could solve any Wheatstone-Plett cryptograms. In 1918 the U.S. considered using it as a tactical encoder. They submitted it to Riverbank Labs for a final security check where the combined team of William and Elizabeth Friedman solved the device within three hours. The exact provenance of the Wheatstone-Plett device pictured below is unknown at this time.