Here’s an encrypted postcard from the early 20th century, which was sent to a young woman in Landreville, France. Can a reader decipher it?
In 1875, a man living in Vienna received an encrypted postcard from a family member. Can you break this cryptogram?
In 1909, an unmarried woman in Santa Monica received a postcard encrypted in an unusual cipher. Can a reader break this encryption?
In 1909, a woman living in Toledo, Ohio, received an encrypted postcard. Can a reader decipher it?
In the early 19th century, an unknown person sent an encrypted postcard from Munich to Berlin. It is not hard to decipher.
In 1905 and 1906 a man named Harry sent a series of encrypted postcards to a friend named Charlie. Can a reader decipher these messages?
In 2008 the magazine “The Canadian Philatelist” published an interesting article about encrypted postcards. Among other things, this article mentions a nice pigpen-enciphered postcard you can try to decipher.
Olivia von Westernhagen, who works as a journalist for the German computer magazine c’t, has provided me an article she wrote, which is based on material she found on my blog. It’s a great read, but it’s available in German only.
Here’s an encrypted postcard from the town of Mannswörth, Austria. Can you decipher it?
A postcard depicting tourist attractions in the Swabian Jura bears an encrypted message. Can you decipher it?