Nowadays a number of enabling technologies are coming together. Above all is the progressive reduction of the cost and scale of computing devices equipped with wireless communication, sensing and actuating capabilities. Sensing capabilities include cameras, microphones, GPS receivers and many different scalar sensors. Open-sourced, general-purpose and easily programmable operating systems are spreading as a result of market forces. These factors create a multitude of devices and smart objects interconnected on a global scale and nowadays called the Internet of Things (IoT). This one emerges by the way as a network of physical objects, devices, vehicles, buildings and other items embedded with electronics, software, sensors, actuators and network connectivity, to enable the collect and the exchange of data. The intrinsic heterogeneity of IoT makes its programming, deployment and management difficult and even crippling. The Web with its almost universal feature, appears as a promising candidate to provide to IoT a platform able to abstract and hide its fundamental heterogeneity. The shift from IoT to the Web of Things (WoT) has mainly to simplify the management of IoT while preserving its full range of capabilities and possibilities. Each smart object in WoT can interact with users and with other smart objects using a RESTfull API either embedded in the smart object itself or in a gateway. It can be accessible through a dedicated URL via a standard web protocol such as HTTP, REST, . . . using the browser as a native access point. This convergence to the web can eventually bring some security issues mainly related to the huge number of possible connected smart objects, which reduces the efficiency or may even invalidate the traditional control mechanisms (identity management, authentication, access control . . . ). We argue thus the need of a deeper investigation of the security requirements of WoT together with an analysis of the limitations of the existing security architectures.