Cicada 3301 is a nickname given to an organization that, on three occasions, has posted a set of puzzles to recruit codebreakers from the public.  The first internet puzzle started on January 4, 2012, on 4chan and ran for nearly a month. A second round began one year later on January 4, 2013, and then a third round following the confirmation of a fresh clue posted on Twitter on January 4, 2014.   The third puzzle has yet to be solved. The stated intent was to recruit "intelligent individuals" by presenting a series of puzzles which were to be solved. No new puzzles were published on January 4, 2015. However, a new clue was posted on Twitter on January 5, 2016.   In April 2017, a verified PGP-signed message was found.  It explicitly denies the validity of any unsigned puzzle. A verified puzzle has not been posted since.
It has been called "the most elaborate and mysterious puzzle of the internet age"  and is listed as one of the "top 5 eeriest, unsolved mysteries of the internet",  and much speculation exists as to its function. Many have speculated that the puzzles are a recruitment tool for the NSA, CIA, MI6, a " Masonic conspiracy"  or a cyber mercenary group.   Others have claimed Cicada 3301 is an alternate reality game. However, no company or individual has attempted to monetize it.  Dark Web: Cicada 3301, a film inspired by the organization, was released in 2021.
The stated purpose of the puzzles each year has been to recruit "highly intelligent individuals", although the ultimate purpose remains unknown.  Some  have claimed that Cicada 3301 is a secret society with the goal of improving cryptography, privacy and anonymity.  Others  have claimed that Cicada 3301 is a cult or religion. According to statements of several people who won the 2012 puzzle, 3301 typically uses non-puzzle-based recruiting methods, but created the Cicada puzzles because they were looking for potential members with cryptography and computer security skills. 
The first puzzle, of 2012, has been solved by Marcus Wanner.  According to him, those who solved the puzzles were asked questions about their support of information freedom, online privacy and freedom, and rejection of censorship. Those who answered satisfactorily at this stage were invited to a private forum, where they were instructed to devise and complete a project intended to further the ideals of the group.  He did not finish his work on a method of general decryption and the website was removed.
The Cicada 3301 clues have spanned many different communication media, including the internet, telephone, original music, bootable Linux CDs, digital images, physical paper signs, and pages of unpublished cryptic books written in runes. One book, titled Liber Primus, literally "first book", contains many pages, only some of which have been decrypted. More information on which pages were solved, and how can be found on the official Cicada 3301 wiki. In addition to using many varying techniques to encrypt, encode, or hide data, these clues also have referenced a wide variety of books, poetry, artwork and music.  Each clue has been signed by the same OpenPGP private key to confirm authenticity.  
Authorities from the Los Andes Province of Chile claim that Cicada 3301 is a "hacker group" and engaged in illegal activities. Cicada 3301 responded to this claim by issuing a PGP-signed statement denying any involvement in illegal activity.  
In July 2015, a group calling themselves "3301" hacked into Planned Parenthood's database;  however, the group appears to have no association to Cicada 3301.  Cicada 3301 later issued a PGP-signed statement stating they "are not associated with this group in any way" and also stated that Cicada 3301 does not "condone their use of our name, number, or symbolism".  The hacker group later confirmed that they are not affiliated with Cicada 3301. 
As the group has gained notoriety and public attention, many have asserted that the puzzles are an introduction to occult principles, and possibly even recruitment for a cult. Tim Dailey, a senior research fellow with the conservative Christian Family Research Council, analyzed the teachings of Cicada 3301, and stated, "The enigmatic Cicada 3301 appears to be drawing participants inexorably into the dark web of the occult à la Blavatsky and Crowley. At the heart of the enchantment is the counterfeit promise of ultimate meaning through self-divination."  
The plot of "Nautilus", the September 30, 2014 episode of the TV show Person of Interest, featured a large-scale game very similar to the Cicada 3301 puzzles. Both feature a series of worldwide cryptographic puzzles, but as the title implies, these feature the image of a nautilus shell instead of a cicada logo.  Person of Interest creator Jonathan Nolan and producer Greg Plageman stated in an interview that Cicada 3301 was the inspiration for the episode: "Episode 2, I'm particularly fascinated by the subject underneath it. Look up Cicada 3301 on the internet. It's a very interesting concept out there that we then put into a larger story that connects to our show." 
The organization is the subject of the comedy-thriller film Dark Web: Cicada 3301, which was announced in 2018.  Directed by Alan Ritchson, who co-wrote the script with Joshua Montcalm, it stars Jack Kesy, Conor Leslie, Ron Funches, Kris Holden-Ried, Andreas Apergis, and Ritchson. The film was acquired by Lionsgate in 2020,  who released the film digitally on March 12, 2021.  
Cicada 3301 is mentioned in the 5th episode "Game Over" of Q Into the Storm.
There were two pieces of music, titled 'the Instar Emergence' and 'Interconnectedness,' accompanying the Cicada clues. However, none of them were part of a standard repertoire, and neither the composers nor performers have been identified. Certain patterns have emerged that indicate that the music itself may be a clue and that Cicada is attempting to establish a musical cryptogram in parallel with its other embedded information. TechGeek365 analyzed the structure of a number of the pieces and discovered that there are certain dyads (two notes sounding simultaneous), which, when corresponded with letters and numbers, reveal hidden messages. However, TechGeek365's analysis is not done on verified Cicada 3301 content.  
Artists Rick Steff and Roy Berry of the band Lucero included a Cicada 3301-inspired song on their side-project album Superfluidity. The music video, directed by Charlie Fasano, featured artwork taken from the Liber Primus book by Cicada 3301. 
- "The internet mystery that has the world baffled". The Daily Telegraph. 25 November 2013. Archived from the original on 25 November 2013. Retrieved 25 November 2013.
- Bell, Chris. "Cicada 3301 update: the baffling internet mystery is back". The Daily Telegraph. Archived from the original on April 12, 2018. Retrieved April 5, 2018.
- Hern, Alex (January 10, 2014). "Cicada 3301: I tried the hardest puzzle on the internet and failed spectacularly". The Guardian. Archived from the original on December 21, 2016.
- Puzzle Image, archived from the original on 2016-01-16, retrieved 2016-05-14
- Cicada 3301. "Cicada 3301's new puzzle (Dead Image)". Archived from the original on May 7, 2016.
- Threat Stack. "Cicadas & Security, Part 2: When a Verified PGP Key Takes You on a Trip to the Desert".
- "Is mystery internet challenge a recruiting tool for the CIA?". Channel 4 News. 27 November 2013. Archived from the original on 28 August 2015. Retrieved 27 November 2013.
- Lipinski, Jed. "Chasing the Cicada: Exploring the Darkest Corridors of the Internet". Mental_Floss. Archived from the original on 20 September 2015. Retrieved 17 December 2012.
- Ernst, Douglas (November 26, 2013). "Secret society seeks world's brightest: Recruits navigate 'darknet' filled with terrorism, drugs". The Washington Times. Archived from the original on 25 September 2015. Retrieved 13 December 2013.
- Bell, Chris (7 January 2014). "Cicada 3301 update: the baffling internet mystery is back". The Daily Telegraph. Retrieved 10 January 2014.
- Scott, Sam (16 December 2013). "Cicada 3301: The most elaborate and mysterious puzzle of the internet age". Metro. Retrieved 16 December 2013.
- Dewey, Caitlin (21 May 2014). "Five of the Internet's eeriest, unsolved mysteries". The Washington Post. Retrieved 2 May 2014.
- Vincent, James (7 January 2014). "Masonic conspiracy or MI6 recruitment tool? Internet mystery Cicada 3301 starts up again". The Independent. Retrieved 2 October 2017.
- Kushner, David (29 January 2015). "Cicada: Solving the Web's Deepest Mystery" (1227). Rolling Stone. Retrieved 20 June 2015.
- Tucker, Daniel (30 December 2013). "Meet the Teenage Codebreaker Who Helped Solve the Cicada 3301 Internet Puzzle". NPR/WNYC New Tech City. Retrieved 13 May 2014.
- Dailey, Timothy (2015-07-07). The Paranormal Conspiracy: The Truth about Ghosts, Aliens and Mysterious Beings. Chosen Books. pp. 145–161. ISBN 978-0800797768.
- "Cracking the Code of Cicada 3301". YouTube. Great Big Story. Retrieved 23 May 2020.
- Mihai, Andrei (April 28, 2014). "Cicada 3301: A puzzle for the brightest minds, posted by an unknown, mysterious organization". ZME Science. Retrieved February 26, 2015.
- Andes Online. "PDI advierte sobre nueva modalidad de estafa por internet a través de google". Andes Online.
- Pastebin. "PGP signed Cicada message".
- Oh, Inae. "Anti-Abortion Hackers Claim to Have Stolen Data That Could Take Down Planned Parenthood". Mother Jones. Retrieved 28 July 2015.
- Turton, William. "Anti-abortion hackers attack Planned Parenthood, release databases, employee data". Daily Dot. Retrieved 28 July 2015.
- 3301, Cicada. "Public Statement".CS1 maint: numeric names: authors list ( link)
- Hacker Group. "Public Statement".
- Ross, Benjamin (2015-05-05). Millennial Mysticism (1 ed.). pp. 115–121. ISBN 978-1512043051.
- McEvoy, Maria (30 April 2014). "US Navy attempting to recruit cryptologists through Facebook game". Telegraph. Retrieved 1 May 2014.
- Stanely, T.L. "The U.S. Navy Wants You – To Solve This Puzzle". Mashable. Retrieved 1 May 2014.
- Planje, Alexa (1 October 2014). "Review: Person Of Interest: 'Nautilus'". A.V. Club. Retrieved 1 October 2014.
- Roffman, Marisa. "Person of Interest Season 4: Greg Plageman and Jonathan Nolan Tease a Cold War, the Loss of Sanctuary, and More". Give Me My Remote. Retrieved 7 October 2014.
- Hipes, Patrick (6 March 2018). "Phreaker Films Launches With Silicon Valley VC Cash; Alan Ritchson To Run It". Deadline. Retrieved 14 October 2019.
- Ramos, Dino-Ray (10 September 2020). "Grindstone Acquires Alan Ritchson's Comedy-Thriller 'Cicada 3301'". Deadline Hollywood. Retrieved 10 September 2020.
- Adams, Tim (13 January 2021). "Dark Web: Cicada 3301 Red-Band Trailer Recruits Titans Stars". Comic Book Resources. Retrieved 28 January 2021.
- Price, Jason (14 January 2021). "'Dark Web: Cicada 3301' – Cyber-Thriller Starring Alan Ritchson Hits Digital and On Demand March 12!". Icon Vs. Icon. Retrieved 28 January 2021.
- "Coded Music In Cicada 3301? - TechGeek365". TechGeek365. 2016-12-10. Retrieved 2017-10-25.
- "Yes, It's Another Bit Of Cicada Cryptomusic! - TechGeek365". TechGeek365. 2017-01-12. Retrieved 2017-10-25.
- McCoy, Chris. "Music Video Monday: Rick & Roy". Memphis Flyer. Contemporary Media. Retrieved 7 December 2015.