A postcard from 1885 was written in a strange code. Can a reader decipher it?
Tobias Schrödel, Germany’s number one comedy hacker and crypto book expert, has provided me another encrypted postcard. Here’s the address side of it:
Apparently, this card was sent from Zurich, Switzerland, to Hamburg, Germany, in 1886. The recipient was a certain Henry (?) M. Rosenberg, living in Grosse Bleichen, a well-known street in central Hamburg. Grosse Bleichen is located close to the Aussenalster, which is the place where the Altster bottle posts were found over a century later (no, I don’t think that there is a relationship).
As readers of this blog know, encrypted postcards are nothing uncommon. I have introduced dozens of them on this blog. However, this one looks different from all others I have seen so far. Here’s the encrypted message:
This postcard was written in 1885, which makes it one of the oldest encrypted postcards I have ever seen (the only older one I remember was written in 1875, also from Switzerland). Usually, encrypted postcards were written by young men to their spouses, but this one looks more like a business message (at least today, Grosse Bleichen is a place where many businesses are located) .
The encrypted text passages (there are two, numbered VII and VIII) look unusual, too. Unlike most other encrypted postcards, this one appears not to be enciphered in a MASC.
There is a lot of regularity in the ciphertext. For instance, in the first passage (VII), we find the numbers 29, 30, 32, 34, 37, 42, 43, 44, 45, 47, 51, 52, 53 (in this order, but with some interruptions). This means that there is not much entropy contained. Maybe, these numbers refer to catalog entries or something similar.