publication date: Saturday, January 29, 2022 (part of Winter 2022)

category: Mysteries

clue: If this Stonehenge-loving Redditor was 2bda2998d9b0ee197da142a0447f6725, then I don't want to be 7c4f29407893c334a6cb7a87bf045c0d.

explanation: A858DE45F56D9BC9, often called just A858, was a Reddit user who created a forum of the same name in 2015 and posted encrypted messages with virtually zero explanation, attracting a large following of Internet sleuths and cryptologists who tried to make sense of it. A few messages were decoded, including one that was an ASCII map of Stonehenge, but most remain undeciphered. The original user deleted their account after a couple of years and stopped posting, but attempts to further understand the messages have continued. more…

intended difficulty: very hard

solved by: Russ Wilhelm, Steve West, and Samir Mehta

trivia: The clue contains the MD5 hashes for the words "wrong" and "right."

Similar Goos

Ken McElroy

This midwestern town bully was shot in broad daylight with dozens of witnesses yet his killer was never identified. Go »

Amelia Earhart

Sorry, this goo crashed with only 7,000 bytes left in the upload. Go »

Grigori Perelman

After 100 years, the million-dollar solution to a French geometric mystery has come from St. Petersburg, by a man who wants nothing to do with the field. Go »

D.B. Cooper

If this notorious (and anonymous) hijacker was ever arrested, he'd definitely be considered a flight risk. Go »

Madeleine McCann

The words "little girl lost" (or their Portuguese equivalent) launched a worldwide media investigation one year ago. Go »

Johnny Gosch

Gosh, I hope this paperboy finishes his route soon. Go »