## A dictionary code challenge

A century ago, cryptologist André Langie reported about a really difficult dictionary cryptogram he had allegedly solved? Was it a strike of genius? Or was it a lie? Here is a similar challenge.

## A Rubik’s Cube encryption challenge

A Rubik’s Cube can be used to implement a low-tech encryption method. But is it secure? Here’s a challenge for my readers to solve.

## Update: A complete (?) list of German cipher machines in World War 2

Two years ago, I published a list of all German WW2 encryption machines I was aware of. Meanwhile, I have some new information. Here’s an update.

## An unsolved cryptogram by a German conquistador

German adventurer and explorer Philip von Hutten (1505-1546) left behind an encrypted note that has never been deciphered. Can a reader of this blog solve this mystery?

## Unsolved cryptograms from the Thirty Years’ War (2)

Here are a few more encrypted texts Peter Nüchterlein, the writer-in-residence in Wernigerode, Germany, has found in a Vienna archive. Can a reader decipher them?

## Who can decipher this encrypted note from Italy?

Italian crypto history expert Paolo Bonavoglia has forwarded me a 19th century shorthand note from Italy. Can a reader decipher it?

## Revisited: A 19th century Bible code

Two years ago, I blogged about five encrypted 19th century newspaper ads that contain Bible references. Blog reader Thomas Ernst found an interesting solution approach, but so far nobody has deciphered these cryptograms.

## Unsolved cryptograms from the Thirty Years’ War (1)

Peter Nüchterlein, the writer-in-residence in Wernigerode, Germany, has asked me for help. In a Vienna archive he has found over 100 encrypted documents from the Thirty Years’ War. Today, I am going to introduce five of them. Can a reader decipher them?

## An unsolved Pigpen graffiti

Can you decipher this encrypted graffiti that was found near Rome, Italy? The encryption method used looks like a Pigpen variant.

## Talon: A playing card cipher

Designing a secure manual encryption algorithm is a challenge. Some cryptographers have developed ciphers that require a deck of playing cards. The best-known one of this kind is Bruce Schneier’s Solitaire. Today, I am going to introduce another one: Talon by Aaron Toponce.