NSA/CSS @NSAGov
#DYK the National Cryptologic Museum houses 2 of the oldest books published on cryptology? Polygraphiae, published in 1518, and the Opus Novum of Jacopo Silvestri, published in 1526. These 2 books represent the oldest–and rarest–books on cryptology in the Western World. #TBT https://t.co/aNBy1KjnhE — PolitiTweet.org