42 characters
Jefferson-type cipher · 42 chars/disk
National Cryptologic Museum Jefferson-type wheel cipher specimen with 42 characters hand-painted on each disk.
The National Cryptologic Museum holds an incomplete Jefferson-type cipher cylinder. It began with 40 disks. 35 remain. Each disk has 42 characters hand-painted in black, including French letters, accents, punctuation, and numbers. It dates to the second quarter of the nineteenth century. It is not Jefferson's own device.
What it supports
An exact 42 on a named museum cipher object in the Jefferson-disk tradition. The Cryptologic Foundation page states the 42-character fact.
What it does not
Not Jefferson's own 26-letter English wheel. Not Jefferson's personal device. Not the U. S. Army M-94 alphabet. Not Adams.
ExactnessExact
Form42
Unitcharacters
Strengthattested
Hung26 September 2026