Secure Compare Rotator

The ActiveSupport::SecureCompareRotator is a wrapper around ActiveSupport::SecurityUtils.secure_compare and allows you to rotate a previously defined value to a new one.

It can be used as follow:

rotator = ActiveSupport::SecureCompareRotator.new('new_production_value')
rotator.rotate('previous_production_value')
rotator.secure_compare!('previous_production_value')

One real use case example would be to rotate a basic auth credentials:

class MyController < ApplicationController
  def authenticate_request
    rotator = ActiveSupport::SecureCompareRotator.new('new_password')
    rotator.rotate('old_password')

    authenticate_or_request_with_http_basic do |username, password|
      rotator.secure_compare!(password)
    rescue ActiveSupport::SecureCompareRotator::InvalidMatch
      false
    end
  end
end