Fourteen years ago, a Reddit user named A858DE45F56D9BC9 began posting seemingly meaningless characters in a subreddit of the same name. For over a year, these posts went largely unnoticed until, unexpectedly, a wave of interest surged. This led to the formation of a community filled with thousands of individuals obsessed with solving the puzzle and unearthing the identity behind what is considered one of the biggest Internet mysteries .
Reddit’s Stonehenge
Known colloquially as The Mystery of A858, the saga began in July 2011. While early posts were ignored, things changed in 2012 when the Reddit community started to take notice. Users attempted to decipher the cryptic messages, and one significant response caught everyone’s attention.

<span>The comment and the answer confirmed that A858 was not "something", but "someone."</span>A user aptly labeled A858 as Reddit’s Stonehenge, alluding to its enigmatic function. Soon after, A858 responded with an encrypted message that turned out to be an ASCII art representation of—fittingly—Stonehenge. This revelation shifted the narrative, demonstrating that there was a human behind A858. What followed was an eruption of interest and frenzy within the community.
Years Trying to Solve It
With growing curiosity and intrigue, users aimed to uncover the motivations behind the cryptic posts. By September 2012, the SOLVINGA858 COMMUNITY emerged, which currently boasts over 15,000 members. This platform became a hub for a collected effort to decipher A858’s purpose, and the struggle persisted for years.
Deciphering A858 proved to be exceptionally difficult. The user exhibited strange behavior, disappearing and deleting posts at random, leaving the community frustrated.
Although several messages were unraveled—featuring quotes from literary figures, Christmas greetings, and even references to April Fools’ Day—the complex nature of A858’s posts continued to baffle the community. The cryptic content utilized unusual obfuscation techniques, resulting in an unpredictable range of challenges. While some messages were relatively simple to decode, others seemed utterly impossible, leading to fluctuating levels of enthusiasm within the community.

Ask A858 Anything
The turning point occurred in 2015 when A858 hosted an AMA (Ask Me Anything) session. This interaction answered numerous questions from users but also left many in the dark. A858 assured the community that they weren’t wasting their time but remained tight-lipped about the true aims behind the project.
During the session, A858 disclosed that only one individual from the United Kingdom had successfully deciphered them, expressing hopes for more correct answers. Here are some highlighted interactions from the session:
What is R/A858DE45F56D9BC9?
The objective cannot be revealed.
A858 published ASCII art drawings, prime numbers tables, etc. Were you just playing with us?
These coded posts were designed to be solvable.
So, why were others encrypted using higher security?
The tougher ones were not meant to be easily resolved.
There are often long pauses without posts from A858. Is this your full-time job?
Sometimes we are touching things up; other times, we are involved in other projects.
Is A858 a solo project, or do you work as part of a team?
A858 is a team effort. I am just one member.
Are you affiliated with any government organization?
I can’t think of a place that doesn’t have a government.
An Unsolved Mystery
Though the AMA added layers to the intrigue, over time, A858 began posting with less frequency until all communication ceased. By March 2016, after months of inactivity, a message appeared claiming, “The A858 project has concluded.” Many users were left skeptical, but A858 never posted again.
A858’s mystery remains unsolved, with the only certainty being the corporate entity behind it had cut funding.
The next notable update came in September 2016 when one of the moderators of the Solving A858 subreddit claimed to have contacted the person behind A858. According to the reveal, A858 was funded to “post code puzzles through encryptions and text handling methods.” Eventually, the company’s withdrawal of funding led to the project’s abrupt conclusion, leaving many questions unanswered and frustrated members.

Theories Behind A858
As with any compelling mystery, various theories have emerged surrounding the true nature of A858. A prevalent hypothesis suggests it was a recruiting initiative aimed at finding experts in encryption. The narrative draws parallels with Cicada 3301, another intricate puzzle with a more straightforward resolution. Allegedly, successful decipherers received invitations to join a secretive organization.
Another theory posits that A858 was a ‘Numbers Station’, employed by Mossad for espionage. While this remains speculative, a more plausible theory supports that A858 served as a company’s security test. In this scenario, the goal of the initiative was for individuals to solve the puzzles, thereby affirming their security protocols were effective. If this was indeed the case, they succeeded masterfully.
Image | Amparo Babyloni, Xataka
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