Two years ago, I blogged about a beautiful encrypted postcard sent by a man named Fritz to his lover Leni. A blog reader has now made aware of a similar card from the same sender.

The keywords used for the Double Columnar Transposition (DCT) should have relatively prime lengths. But why?

John Haas and Christian Baumann, two blog readers who met when I invited both of them to a get-together in Vienna, have started an interesting project.

A British scientist has discovered four paper sheets that were originally a part of the Voynich Manuscript. This exciting find might finally lead to a reliable dating of the mysterious book.