Keychain - store service keys encrypted in rails config

keychain.gemspec

Gem::Specification.new do |s|
  s.name          = "keychain"
  s.files         = ['keychain.rb']
  s.require_path  = '.'
  s.version       = '0.0.1'
  s.add_runtime_dependency 'aes', '~> 0.5.0'
end

keychain.rb

require 'aes'

module Keychain
  class << self
    def get(keyname)
      encrypted_key = keys[keyname]
      AES.decrypt(encrypted_key, encryption_key)
    end

    def set(keyname, key)
      keys[keyname] = AES.encrypt(key, encryption_key)
      File.open("#{Rails.root}/config/keychain.yml", 'w') {|f| f.write keys(false).to_yaml }
    end
  
    def encryption_key
      ENV['MAIN_KEY'] || 'development'
    end
  
    def keys(env=true)
      @keys ||= YAML.load_file("#{Rails.root}/config/keychain.yml")
      env ? @keys[Rails.env] : @keys
    end
  end  
end

keychain.yml

production:
  rollbar: kLAAHj74VmV+nRwl+XGNnQ==$BiFlxL6ze81lIgJ3ZargofpS3nqMtRLjX8Flt4m2L84YtUxl2o=
staging:
  rollbar: z3mvkFv8J/6A==$LVrFWmJaCxbyzrjaeJtqdQ6QjO4uOKnMHKfa9iDYtUxl2oUHq+LjXFkVSJOu=