class WebSocket::Driver::Draft76

def handshake_signature
  return nil unless @body.bytesize >= BODY_SIZE
  head   = @body[0...BODY_SIZE]
  env    = @socket.env
  key1   = env['HTTP_SEC_WEBSOCKET_KEY1']
  value1 = number_from_key(key1) / spaces_in_key(key1)
  key2   = env['HTTP_SEC_WEBSOCKET_KEY2']
  value2 = number_from_key(key2) / spaces_in_key(key2)
  Digest::MD5.digest([value1, value2, head].pack('N2A*'))
end