In 1914, a man sent an encrypted postcard from Kiel to Hannoversch Münden. Contrary to all other encrypted postcards I know, this one was written with a typewriter.

Yesterday, I was at the ITSA in Nuremberg, Europe’s leading IT security exhibition. I took part in a conference about usability in IT security hosted by the German Ministery of Economics and organized by my friend Hellen Takenberg. The first presentation was given by Tobias Schrödel, …

Source: Schmeh

… known to my readers as the world’s best comedy hacker. After Tobias, it was my turn.

Source: Sasse

Like always, I used comic figures and Lego models for my presentation, which was well received. The third talk was given by another friend of mine, Angela Sasse.


A postcard written with a typewriter

Tobias is not only a great comedian but also a collector of encrypted postcards. I have blogged about many of the treasures in his collection. Today, I am going to introduce another one. The special thing about it is that it was written with a typewriter. I have never seen postcard of this kind before. Here’s the picture side:

Source: Schrödel

The pictures show motives from Kiel, a North German harbor city on the Baltic Sea. Here’s the text side:

Source: Schrödel

Contrary to many other postcards, this one is easy to read. According to the top line, it was written in Kiel on March 23rd, 1914. The recipient is an unmarried woman (“Fräulein”) named Lina Kellner living in Hannoversch Münden, a town between Kassel and Göttingen, Germany. Still today, there are people named Kellner living in Hannoversch Münden.

Most encrypted postcards were written by young men to their spouses. I don’t think that this one is an exception.


The solution

It is not very hard to break this encryption. The ciphertext expression “Efnm” in the second line stands for Lina, the name of the recipient. Other letters can easily be guessed. Can a reader decipher the rest of this cryptogram?

Further reading: An encrypted postcard from the Isle of Wight


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Kommentare (4)

  1. #1 gnaddrig
    11. Oktober 2019

    This is quite simple (not so much if you don’t speak German, though) and didn’t take long to break. But then, the text is harmless enough:

    Alfnl eflbl Hfnm!
    Meine liebe Lina!
    My dear Lina!

    Uflr olndl fcu Dfr
    Hier sende ich Dir
    Here I send you

    lfnl Mnofcut vsa
    eine Ansicht vom
    a view of

    Kflelr-Umiln hnd dlr
    Kieler-Hafen und der
    Kiel harbour and the

    Imperial ship-

    wlrit. Dfl blotln
    werft. Die besten
    yard. Best

    Grffool hnd Kffool
    Griisse und Kiisse
    Greetings and Kisses [with ii instead of the ü umlaut in both words]

    vsn Dlfnln trlhln
    von Deinen[sic!] treuen
    from your [with a grammatical slip] faithful


    Erich didn’t use all letters of the alphabet, and he swapped just a few: A for M and M for A, likewise F – I, E – L, H – U, O – S.

  2. #2 Gerd
    12. Oktober 2019

    >Erich didn’t use all letters of the alphabet,
    >and he swapped just a few: A for M and M for A,
    >likewise F – I, E – L, H – U, O – S.

    So we should call this method a “Steckerbrett”-cipher? It works like an enigma steckerbrett with only 5 cords plugged.


  3. #3 Gerd
    12. Oktober 2019

    Note that this simple way of “cipher” can be done with the help of a slightly modified typewriter, i. e. exchanging key caps or placing stickers over the keys. Maybe this is why this one is writen with a typewriter.

  4. #4 Klaus Schmeh
    13. Oktober 2019

    @gnaddrif, Gerd:
    Thank you very much! Another mystery solved.