# File lib/webrick/httpauth/digestauth.rb, line 34
      def initialize(config, default=Config::DigestAuth)
        check_init(config)
        @config                 = default.dup.update(config)
        @algorithm              = @config[:Algorithm]
        @domain                 = @config[:Domain]
        @qop                    = @config[:Qop]
        @use_opaque             = @config[:UseOpaque]
        @use_next_nonce         = @config[:UseNextNonce]
        @check_nc               = @config[:CheckNc]
        @use_auth_info_header   = @config[:UseAuthenticationInfoHeader]
        @nonce_expire_period    = @config[:NonceExpirePeriod]
        @nonce_expire_delta     = @config[:NonceExpireDelta]
        @internet_explorer_hack = @config[:InternetExplorerHack]
        @opera_hack             = @config[:OperaHack]

        case @algorithm
        when 'MD5','MD5-sess'
          @h = Digest::MD5
        when 'SHA1','SHA1-sess'  # it is a bonus feature :-)
          @h = Digest::SHA1
        else
          msg = format('Alogrithm "%s" is not supported.', @algorithm)
          raise ArgumentError.new(msg)
        end

        @instance_key = hexdigest(self.__id__, Time.now.to_i, Process.pid)
        @opaques = {}
        @last_nonce_expire = Time.now
        @mutex = Mutex.new
      end