The British mail authority has issued a set of six stamps devoted to crime writer Agatha Christie. The stamps are packed with steganographic messages. Can you find them?
A British censorship manual from WW2 gives an overview on message hiding techniques. Some of the examples given are messages hidden in letters from prisoners of war.
A researcher from Liechtenstein has asked me for help. She has encountered three partially encrypted letters from the early 19th century. Can a reader decrypt them?
Today’s post is about a book with strange illustrations written in an unknown script. This book still waits to be deciphered. And no, I’m not talking about the Voynich manuscript.
130 years ago, Briton Alfred Janes published a self-invented encryption method along with a challenge cryptogram. My blog readers could solve this tricky mystery.
A crypto book published in 1808 contains an exercise cryptogram. The solution is not given. Can you find it?
Three encrypted postcards from San Francisco are discussed in an internet forum. The solutions still seem to be unknown. Can a reader of this blog help?
Bérenger Saunière (1852-1917) was a French preacher, who has become famous among conspiration theorists and Dan Brown readers. A cryptogram he allegedly left behind is said to have led to a treasure.
An encrypted bottle post was found in Kaliningrad, Russia, in 2015. As it seems, the cleartext is still unknown. Can a reader break this unusual cryptogram?