Block_CTF(1) Block_CTF(1)

Name

BlockCTF - Capture the Flag competitions, hosted by Block, where teams compete to solve security-related challenges for points.

New to CTFs?

Our CTFs are meant to be fun for both first time and experienced players. We create an assortment of easy, medium, and hard puzzles.

We aspire to create a few novel puzzles, putting everyone on the same level.

We have a list of tips that should help you get started. Some of our previous years' challenges and their solutions are made available to you. You are free to use the content on this site as you please — you may even flatter us by copying bits and pieces for your own event!

Events

• 2024: 13 Nov. 22:00 UTC — 14 Nov. 22:00 UTC. Register here!
• 2023: challenges, writeups and results
• 2022: challenges, writeups and results
• 2021: challenges, writeups and results
• 2020: challenges, writeups and results
• 2019: challenges, writeups and results
• 2018: challenges, writeups and results
• 2017: challenges, writeups and results
• 2016: Slack bots have gained self awareness and are reading the news (private event).
• 2015: BrewBOT (private event).
• 2014: Microcorruption: Embedded Security CTF (co-organized) | write up.

Contact

• [email protected]
• Join our BlockCTF Discord server!

Credits

Our CTFs have been possible thanks to Square engineers contributing their time, skills and energy. Every year, about a dozen engineers get together to build puzzles, as well as spin up all the infrastructure needed to run a smooth competition. We hope you find these puzzles fun and educational, we definitely enjoy making them!

• Mat Byczkowski: Puzzles (2019)
• Paras Chetal: Puzzles (2023)
• Leon Chou: Puzzles & Infrastructure (2020)
• Peter Collins: Infrastructure & puzzles (2017)
• Manoj Dayaram: Infrastructure (2017)
• Alex Epifano (2021)
• Stefan Filipek: Puzzles & Infrastructure (2023)
• Kyle Fox:
  Organizer (2020, 2021, 2022, 2023)
  Puzzles & Infrastructure (2018, 2020, 2021, 2022, 2023)
• Davis Gallinghouse: Puzzles (2015, 2016)
• Daniel Ge: Infrastructure (2018)
• Ross Glashan: Puzzles (2017, 2018)
• Alex Hanlon: Puzzles (2022, 2023)
• Sarah Harvey: Chief CTF Officer (2017)
• Adam Jimenez: Puzzles (2020, 2023)
• Bart Kosciarz: Puzzles (2023)
• John Lewis: Creative writing (2015, 2016)
• Aaron Lindsey: Puzzles & Infrastructure (2022, 2023)
• Kent Ma: Puzzles & Infrastructure (2022, 2023)
• Jack Maginnes: Puzzles (2022)
• Will McChesney: Puzzles (2017)
• Matthew McPherrin: Prizes & puzzles (2016, 2017)
• Jordan Mecom: Puzzles 2017 (2018)
• Alok Menghrajani:
  Organizer (2015, 2016, 2017, 2018, 2019)
  Puzzles (2015, 2016, 2017, 2018, 2019, 2022)
• Dan Moore: Puzzles & Infrastructure (2022)
• Murtaza Munaim: Puzzles (2017)
• Jesse Peirce: Workshop & creative writing (2017, 2018)
• Ford Peprah: Puzzles (2018)
• Achintya Prakash: Infrastructure & puzzles (2018, 2019)
• Alyssa Ransbury: Puzzles (2019)
• Mathew Rowley: Puzzles (2017)
• Isaac Semaya: Puzzles (2020, 2021)
• Jay Smith: Puzzles (2021)
• Salvatore Testa: Puzzles & creative writing (2017, 2019)
• Alice Wang: Puzzles (2017, 2018)
• Brian Wang: Puzzles (2017)
• Jared Windover: Design (2018)
• Roy Xu: Puzzles (2019, 2020, 2021)
• Bushi Zhang: Art work (2019)
• Chaoshun Zuo: Puzzles (2023)

+ everyone who has helped us in various ways. Including making sure our puzzles are solvable, publicizing our events and helping out with last minute show stoppers.

We are also thankful to everyone who took the time to publish writeups/solutions!

See also

Work_at_Block(1), Privacy_policy(1), Code_of_conduct(1)