1500s French encryption device. Gilt brass and gold. Held by The Met, but not on display now.
Fullsize image: https://diqn32j8nouaz.cloudfront.net...e_fullsize.jpg
https://diqn32j8nouaz.cloudfront.net...ion_device.jpg
More:
https://www.metmuseum.org/art/collection/search/771686
https://en.wikipedia.org/wiki/Cryptography
