cookie_decryptor

CookieDecryptor

When you're trying to debug cookie session problems, are you stuck with cookies that look like this?

Set-Cookie: _session_my_app=OXJ2SkhNaFZBWDd1eDU3djhSekZRdmN6WjNKUjN4dlBiMWt3bW9sVjM0OERIZ3lPUmV1UFB2MmlySzI0OXJtbTRDdmI3TGd0S3AvMVNjdTlueEo1Y05zMnE3NTdsMVVmWWFVSXA5NVFOT0U9LS1tM21SL2tIMGhxYjFEWjZjb2Y3ZWlnPT0%3D--533f89e5525959c122e31ff7eae5b886b2ed7fe9; path=/; HttpOnly

What does that even mean? How do you figure out that that cookie decodes to

{"session_id":"35481e34ef3c0d0ac83e4dccf8520120","name":"Justin"}

without faking the session yourself?

With CookieDecryptor, you can paste that header in and get the result right back out.

irb(main):001:0> CookieDecryptor.decrypt("Set-Cookie: _session_my_app=OXJ2SkhNaFZBWDd1eDU3djhSekZRdmN6WjNKUjN4dlBiMWt3bW9sVjM0OERIZ3lPUmV1UFB2MmlySzI0OXJtbTRDdmI3TGd0S3AvMVNjdTlueEo1Y05zMnE3NTdsMVVmWWFVSXA5NVFOT0U9LS1tM21SL2tIMGhxYjFEWjZjb2Y3ZWlnPT0%3D--533f89e5525959c122e31ff7eae5b886b2ed7fe9; path=/; HttpOnly")
=> "{\"session_id\":\"35481e34ef3c0d0ac83e4dccf8520120\",\"name\":\"Justin\"}"

Installation

Add this line to your application's Gemfile:

gem 'cookie_decryptor'

And then execute:

$ bundle

Or install it yourself as:

$ gem install cookie_decryptor

Usage

You can decrypt cookie data with CookieDecryptor.decrypt:

CookieDecryptor.decrypt("OXJ2SkhNaFZBWDd1eDU3djhSekZRdmN6WjNKUjN4dlBiMWt3bW9sVjM0OERIZ3lPUmV1UFB2MmlySzI0OXJtbTRDdmI3TGd0S3AvMVNjdTlueEo1Y05zMnE3NTdsMVVmWWFVSXA5NVFOT0U9LS1tM21SL2tIMGhxYjFEWjZjb2Y3ZWlnPT0%3D--533f89e5525959c122e31ff7eae5b886b2ed7fe9")

Or you can be extra lazy, and paste an entire HTTP cookie header:

CookieDecryptor.decrypt("Set-Cookie: _session_my_app=OXJ2SkhNaFZBWDd1eDU3djhSekZRdmN6WjNKUjN4dlBiMWt3bW9sVjM0OERIZ3lPUmV1UFB2MmlySzI0OXJtbTRDdmI3TGd0S3AvMVNjdTlueEo1Y05zMnE3NTdsMVVmWWFVSXA5NVFOT0U9LS1tM21SL2tIMGhxYjFEWjZjb2Y3ZWlnPT0%3D--533f89e5525959c122e31ff7eae5b886b2ed7fe9; path=/; HttpOnly")

If you're inside your Rails app, CookieDecryptor will default to using your Rails app's secret_key_base. If you're not in a Rails app, or if you want to use a different secret_key_base, you can specify it:

CookieDecryptor.decrypt("OXJ2SkhNaFZBWDd1eDU3djhSekZRdmN6WjNKUjN4dlBiMWt3bW9sVjM0OERIZ3lPUmV1UFB2MmlySzI0OXJtbTRDdmI3TGd0S3AvMVNjdTlueEo1Y05zMnE3NTdsMVVmWWFVSXA5NVFOT0U9LS1tM21SL2tIMGhxYjFEWjZjb2Y3ZWlnPT0%3D--533f89e5525959c122e31ff7eae5b886b2ed7fe9", secret_key_base: "1c81d82d9be8b21667f16b254da480cbbd0fd9fdf856ea88a285479e1bec9860cb3fdda0b214a25e34b16d83929ae87ec846648c7ef5cef35121f029c341ad7b")

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/justinweiss/cookie_decryptor. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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