20 years ago, Jim Gillogly, a great codebreaker and reader of this blog, created three crypto challenges – a Playfair, a Double Playfair, and a Double Column Transposition. Can you solve them?
Three months ago, I presented a terminology for codes and nomenclators, based on a workshop that took place at the HistoCrypt conference. After having received some interesting feedback, I can now provide an update.
A message written 118 years ago in Aldino, Maryland, waits to be solved. Can you break this cryptogram?
The Vernam cipher is mentioned in dozens of cryptography books. It is simple and more secure than most other basic encryption methods. Can you solve the three Vernam challenges I am going to introduce today?
An advertisment poster an Instagram user has seen in a New York subway is completely encrypted. Can you decipher it? And can you tell me what is behind the “spiritual consultancy” that has published this poster and a few others?
In the Cold War, US scientist Gus Simmons discovered a serious weakness in a cryptologic disarmament technology. His discovery initiated a new branch of IT security. Nevertheless, nobody seems to know how this weakness worked. The paper Simmons published about it doesn’t contain a detailed description. Does a reader know more?
Can a reader decipher this encrypted diary page I found on the internet? I don’t know by whom and when it was written, but I’m sure that it can be solved.
A Reddit user has posted an encrypted note he found in a family member’s personal effects. The cleartext is not known. Can you solve it?
Stephen Hawking, the world-famous physicist who died earlier this year, has left behind ten puzzles. One of these has now been published. It looks like a cryptogram.
The German radio station WDR5 has aired a report about Enigma spy Hans-Thilo Schmidt. Among the experts quoted are Dermot Turing and me.
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