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Module command-line tool to parse, create and manipulate JWT tokens for hackers
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A modular command-line tool to parse, create and manipulate JSON Web Token(JWT) tokens for security testing purposes.


  • Complete modularity.
    • All commands are plugins.
    • Easy to add new plugins.
    • Support JWS and JWE tokens.
  • Easy interface for plugins. (follow the template example)
  • Flexible
  • token generation based on production-class libraries (e.g. json-jwt, jwe).

Available plugins

  • Parse: parses jwt tokens.
  • jws: manipulate and generate JWS tokens.
  • jwe: manipulate and generate JWE tokens.
  • bruteforce: brutefocing JWS signing key
  • wiki: contains offline information about JWT, attacks ideas, references.


install it yourself as:

$ gem install jwtear


  • Show the main menu
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    jwtear - Parse, create and manipulate JWT tokens.

    jwtear [global options] command [command options] [arguments...]

    -v, --version - Check current and latest version
    -h, --help    - Show this help message

    help            - Shows a list of commands or help for one command
    bruteforce, bfs - plugin to offline bruteforce and crack token's signature.
    jws, s          - Generate signature-based JWT (JWS) token.
    jwe, e          - Generate encryption-based JWT (JWE) token.
    parse           - Parse JWT token (accepts JWS and JWE formats).
    wiki, w         - A JWT wiki for hackers.
  • Show a subcommand help, use -h COMMAND
$jwtear -h jws

    jws - Generate signature-based JWT (JWS) token.

    jwtear [global options] jws [command options] 

    Generate JWS and JWE tokens. 

    -h, --header=JSON               - JWT header (JSON format). eg. {"typ":"JWT","alg":"HS256"}. Run 'jwtear gen -l' for supported algorithms. (required, default: none)
    -p, --payload=JSON              - JWT payload (JSON format). eg. {"login":"admin"} (required, default: none)
    -k, --key=PASSWORD|PUB_KEY_FILE - Key as a password string or a file public key. eg. P@ssw0rd  | eg. public_key.pem (default: none)
  • Use a plugin

plugins are defined as subcommands. Each subcommand may have one or more argument and/or switches.

$ jwtear parse -t eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.J8SS8VKlI2yV47C4BtfYukWPx_2welF34Mz7l-MNmkE
$ jwtear jws -h '{"alg":"HS256","typ":"JWT"}' -p '{"user":"admin"}' -k p@ss0rd123
$ jwtear jwe -header '{"enc":"A192GCM","typ":"JWT"}' --payload '{"user":"admin"}' --key public.pem 
$ jwtear bruteforce -v -t eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyIjpudWxsfQ.Tr0VvdP6rVBGBGuI_luxGCOaz6BbhC6IxRTlKOW8UjM -l ~/tmp/pass.list

Add plugin

To add a new plugin, create a new ruby file under plugins directory with the following structure

module JWTear
  module CLI
    extend GLI::App
    extend JWTear::Helpers::Extensions::Print
    extend JWTear::Helpers::Utils

    desc "Plugin short description"
    long_desc "Plugin long description"
    command [:template, :pt] do |c|
      c.action do |global, options, arguments|
        print_h1 "Plugin template"
        print_good "Hi, I'm a template."
        template =

  module Plugin
    class TemplatePlugin
      include JWTear::Helpers::Extensions::Print
      include JWTear::Helpers::Utils

      def initialize
        # ..code...
      # ..code...

Instead of including all dependencies for each plugin into jwtear, you can add these dependencies as a hash to check_dependencies method which will require the library and throw a gentle error to the user to install any missing gems.

The hash key is the gem name to install, the hash value is the require string

deps = {'async-io' => 'async/ip'}

Once the missing dependencies are installed by the user, the check_dependencies will require them once the plugin class initiated.


Bug reports and pull requests are welcome on GitHub at[USERNAME]/jwtear.

  1. Fork it ( )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request

Areas to contribute

  • contribution by reporting bugs.
  • contribution by perfecting the current code.
  • contribution by adding new plugins.
  • contribution by enhancing the jwtear wiki.
  • contribution by requesting features and/or plugins.


The gem is available as open source under the terms of the MIT License.

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