ensure_secret_secure

# File actionpack/lib/action_controller/session/cookie_store.rb, line 179
        def ensure_secret_secure(secret)
          # There's no way we can do this check if they've provided a proc for the
          # secret.
          return true if secret.is_a?(Proc)

          if secret.blank?
            raise ArgumentError, "A secret is required to generate an " +
              "integrity hash for cookie session data. Use " +
              "config.action_controller.session = { :key => " +
              "\"_myapp_session\", :secret => \"some secret phrase of at " +
              "least #{SECRET_MIN_LENGTH} characters\" } " +
              "in config/environment.rb"
          end

          if secret.length < SECRET_MIN_LENGTH
            raise ArgumentError, "Secret should be something secure, " +
              "like \"#{ActiveSupport::SecureRandom.hex(16)}\".  The value you " +
              "provided, \"#{secret}\", is shorter than the minimum length " +
              "of #{SECRET_MIN_LENGTH} characters"
          end
        end