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n1474335 edited this page Dec 8, 2016 · 9 revisions

Welcome to the CyberChef wiki pages. Here you can find guides for installing and contributing to CyberChef.

Installing

CyberChef uses the Grunt build system, so it's very easy to install. You'll need to carry out the following steps to get going:

  1. Install Git
  2. Install Node.js and its package manager, npm
  3. Install Grunt: npm install -g grunt-cli
  4. git clone https://github.com/gchq/CyberChef.git
  5. cd CyberChef
  6. npm install

npm will then install all the dependencies needed by Grunt.

Compiling

Grunt has been configured with several tasks to aid in the development process:

grunt dev

Use this when developing new functionality. It will launch a persistent task which will automatically build an uncompressed, development version of CyberChef located in build/dev. Whenever a source file is modified, the development version will be rebuilt.

grunt prod

When you are ready to create a production build, run this command. It will lint, concatenate, and compress all the source files and create a production-ready build in build/prod. It will also create the inline version of CyberChef at the same location.

grunt stats

This command will give you statistics about the code base such as how many lines there are as well as details of file sizes before and after compression.

grunt docs

This will build the codebase documentation and place it in the docs directory.

Coding conventions

  • Indentation: Each block should consist of 4 spaces
  • Object/namespace identifiers: CamelCase
  • Function/variable names: underscore_lower_case
  • Constants: UNDERSCORE_UPPER_CASE
  • Source code encoding: UTF-8 (without BOM)
  • All source files must end with a newline
  • Line endings: UNIX style (\n)

Repository structure

  • build/
    • dev/ - This will be populated with an uncompressed development build of CyberChef by running the grunt dev command.
    • prod/ - This folder contains the most recently built production version of CyberChef including the inline version. It is populated by running grunt prod.
  • src/
    • css/
      • lib/ - Various library CSS files
      • structure/ - Structural styles to lay out the stage
      • themes/ - Look and feel styles
    • html/
      • index.html - The CyberChef page structure
    • js/
      • config/ - Files specifying the operation configurations
      • core/ - Core CyberChef files that make up the heart of the application
      • lib/ - Libraries... oh so many libraries...
      • operations/ - Operation objects
      • views/ - Code to handle the various CyberChef views
        • html/ - The code which makes up the CyberChef web app
    • static/ - Static files like images
  • docs/ - Codebase documentation, populated by running grunt docs.
  • Gruntfile.js - Grunt build process configuration
  • LICENSE - The Apache 2.0 licence information
  • package.json - npm configuration and a list of all the dependencies
  • README.md - An introduction to CyberChef

How to add an operation

  1. Create a new file in the src/js/operations directory and name it using CamelCase. e.g. MyOperation.js

  2. In this file, create a namespace with the same name and populate it with a single function looking like this (all function and variable names should be written in underscore_lower_case):

    var MyOperation = {
    run_my_operation: function (input, args) {
        return input;
    }
};
    • input will be the input data passed on from the previous operation (or the data entered by the user if yours is the first operation). Its data type is specified in the next step by input_type.
    • args will be an array of the arguments for your operation. They are specified in the next step by args.
    • Make sure that you return the output data in the format specified in the next step by output_type.

  3. In src/js/config/OperationConfig.js, create a new entry. For example:

    "The name of your operation": {
    description: "A short description if necessary, optionally containing HTML code (e.g. lists and paragraphs)",
    run: MyOperation.run_my_operation, // a reference to the function that runs your operation 
    input_type: "byte_array", // the input type for your operation, see the next section for valid types
    output_type: "byte_array", // the output type for your operation, see the next section for valid types
    highlight: true, // [optional] true if the operation does not change the position of bytes in the output (so that highlighting can be calculated)
    highlight_reverse: true, // [optional] same as above but for the reverse of the operation (output to input highlighting)
    manual_bake: false, // [optional] true if auto-bake should be disabled when this operation is added to the recipe
    args: [ // A list of the arguments that the user will be presented with
        {
            name: "Argument name",
            type: "string", // the argument data type, see the next section for valid types
            value: MyOperation.DEFAULT_VALUE // the default value of the argument
        }
    ]
}

    For example:

    "XOR": {
    description: "XOR the input with the given key, provided as either a hex or ASCII string.<br>e.g. fe023da5<br><br><b>Options</b><br><u>Null preserving:</u> If the current byte is 0x00 or the same as the key, skip it.<br><br><u>Differential:</u> Set the key to the value of the previously decoded byte.",
    run: BitwiseOp.run_xor,
    input_type: "byte_array",
    output_type: "byte_array",
    args: [
        {
            name: "Key",
            type: "binary_string",
            value: ""
        },
        {
            name: "Key format",
            type: "option",
            value: BitwiseOp.KEY_FORMAT
        },
        {
            name: "Null preserving",
            type: "boolean",
            value: BitwiseOp.XOR_PRESERVE_NULLS
        },
        {
            name: "Differential",
            type: "boolean",
            value: BitwiseOp.XOR_DIFFERENTIAL
        }
    ]
}

  4. In src/js/config/Categories.js, add your operation name to an appropriate list. This determines which menu it will appear in. You can add it to multiple menus if you feel it is appropriate.

  5. Finally, run grunt dev if you haven't already. If it's already running, it should automatically build a development version when you save the files.

  6. You should now be able to view your operation on the site by browsing to build/dev.

  7. You can write whatever code you like as long as it is encapsulated within the namespace you created (MyOperation). Take a look at src/js/operations/Entropy.js for a good example.

  8. You may find it useful to use some helper functions which have been written in src/js/core/Utils.js. These are available in the Utils object (e.g. Utils.str_to_byte_array("Hello") returns [72,101,108,108,111]).

Data types

Input and Output

Four data types are supported for the input and output of operations:

  1. string - e.g. "hello"
  2. byte_array - e.g. [104,101,108,108,111]
  3. number - e.g. 562 or 3.14159265
  4. html - e.g. "<p>hello</p>"

Each operation can define any of these data types as their input or output. The data will be automatically converted to the specified type before running the operation.

Ingredients

Operation arguments (ingredients) can be set to any of the following types:

  1. string or short-string
    • e.g. "hello"
    • A short-string will simply display a smaller input box.
  2. binary_string or binary-short-string
    • e.g. "hello\nworld"
    • Escaped characters entered by the user will be automatically converted to the bytes they represent. A simple string type will return "hello\\nworld" in the above case.
  3. text
    • User is given a textbox for free-flow text.
  4. byte_array
    • e.g. user inputs "68 65 6c 6c 6f", operation receives [104,101,108,108,111].
  5. number
    • e.g. 562
    • This can handle both integer and float values.
  6. boolean
    • User is presented with a checkbox, operation receives true or false.
  7. option
    • Given an array of strings, the user is presented with a dropdown selection box with each of those strings as an option. The selected string is sent to the operation.
  8. populate_option
    • Given an array of {name: "", value: ""} objects, the user is presented with a dropdown selection box with the names as options. The corresponding value will be assigned to whichever argument index the target parameter is set to.
    • See the Regular expression configuration in src/js/config/OperationConfig.js for an example of how this works.
  9. editable_option
    • Given an array of {name: "", value: ""} objects, the user is presented with an editable dropdown menu. The items in the dropdown are labelled with name and set the argument to value when selected.
  10. toggle_string
    • User is presented with a string input box with a toggleable dropdown attached.
    • Populate the dropdown using the toggle_values property.
    • Operation receives an object with two properties: option containing the user's dropdown selection, and string containing the input box contents.
    • Particularly useful for arguments that can be specified in various different formats.
    • See the XOR configuration in src/js/config/OperationConfig.js for an example of how this works.
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