Four episodes of the Zodiac Killer documentary on HISTORY have aired now. The fourth one ended with Craig Bauer saying that he has broken Z340. Will episode 5 tell us the solution?

Two years ago I blogged about an encrypted certificate, which was found in the wall of a house. Nobody could solve this cryptogram. So, it’s time to have a second look at it.

A reader from the Philippines has asked me for help. Can somebody solve the crypto puzzle he is currently working on?

An M4 Enigma from World War II has set a new world record price at a Christie’s auction in New York.

The Masked Man, a German serial killer, was arrested in 2011. Police couldn’t decipher his encrypted storage devices. Now he has revealed his encryption passwords.

Once again, the secret of the world’s most mysterious manuscript has been unlocked. This time the alleged solution comes from Russia. Does this one make more sense than the many others published before?

For centuries nomenclators were the most popular kind of encryption. Still today messages enciphered with a well-designed nomenclator are hard or even impossible to break.

An inscription found on the inside of an old fiddle has never been deciphered.

In one of his books British priest and novelist Sabine Baring-Gould (1834–1924) published a short cryptogram. Can a reader solve it?

In 1906 an unknown person sent an encrypted postcard from St. Petersburg, Russia, to Vaasa, Finland. Can a reader decrypt it?