Before envelopes, people protected messages with letterlocking

Article URL: https://www.atlasobscura.com/articles/what-did-people-do-before-envelopes-letterlocking

Comments URL: https://news.ycombinator.com/item?id=18420924

Points: 41

# Comments: 10

from Hacker News: Front Page https://ift.tt/2DuJKTN
via