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

Methods

Included Modules

Constants

InvalidMatch = Class.new(StandardError)

Class Public methods

new(value, on_rotation: nil)

📝 Source code 
# File activesupport/lib/active_support/secure_compare_rotator.rb, line 37
    def initialize(value, on_rotation: nil)
      @value = value
      @rotate_values = []
      @on_rotation = on_rotation
    end
🔎 See on GitHub

Instance Public methods

rotate(previous_value)

📝 Source code 
# File activesupport/lib/active_support/secure_compare_rotator.rb, line 43
    def rotate(previous_value)
      @rotate_values << previous_value
    end
🔎 See on GitHub

secure_compare!(other_value, on_rotation: @on_rotation)

📝 Source code 
# File activesupport/lib/active_support/secure_compare_rotator.rb, line 47
    def secure_compare!(other_value, on_rotation: @on_rotation)
      if secure_compare(@value, other_value)
        true
      elsif @rotate_values.any? { |value| secure_compare(value, other_value) }
        on_rotation&.call
        true
      else
        raise InvalidMatch
      end
    end
🔎 See on GitHub