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How GCHQ made its CyberChef app open source

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A case study about how GCHQ created an open source app called CyberChef, which assists with cyber operations from within a web browser.

CyberChef is a web app to carry out many cyber operations within a web browser. It has over 300 operations, including basic encoding with Base64, Advanced Encryption Standard (AES) decryption, or changing character encodings. The app can handle many operations at once, making it a quick way to experiment and translate data.

  • was created in an analyst’s 10% ‘innovation time’
  • had its code fully opened in November 2016 under the Apache 2.0 license
  • has been used in almost every country around the world
  • has had 1.4 million unique users since its release
  • has 75 open source community contributors

    • GCHQ is the UK’s intelligence, security and cyber agency with a mission to help keep the UK safe. Its people use cutting-edge technology, technical ingenuity and world-leading partnerships to identify, analyse and disrupt threats in an increasingly complex world.

    GCHQ believes that success depends on great minds not thinking alike. To promote innovation and personal development alongside their usual work, staff are encouraged to spend 10% of their hours on projects of their choosing related to their work. In 2014, an analyst began looking for open tools to help automate some data manipulation operations. It was too time consuming to write short scripts for every data transformation they needed such as encoding, encryption and viewing data in different formats.

    Seeing few open source tools available, they began to develop what would later become known as CyberChef.

    Understanding the CyberChef app’s design

    The CyberChef web app has a simple design and includes:

  • an input box to add the file or text you want to work with
  • a list of all the operations you can run on the file or text
  • a ‘recipe’ box where you can drag the operations you want to use and specify how you want to use them
  • an output box to display the results of your operations

    • This is an extract. The publication continues at the source.

    Read the original at the source: https://www.gov.uk/government/case-studies/how-gchq-made-its-cyberchef-app-open-source

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    Government Communications Headquarters — imported from official source
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    September 20, 2026 19:53
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    https://www.gov.uk/government/case-studies/how-gchq-made-its-cyberchef-app-open-source#...

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