  The evolution of the Internet of Things (IoT) has increased the connection of
personal devices, mainly taking into account the habits and behavior of their
owners. These environments demand access control mechanisms to protect them
against intruders, like Sybil attacks. that can compromise data privacy or
disrupt the network operation. The Social IoT paradigm enables access control
systems to aggregate community context and sociability information from devices
to enhance robustness and security. This work introduces the ELECTRON mechanism
to control access in IoT networks based on social trust between devices to
protect the network from Sybil attackers. ELECTRON groups IoT devices into
communities by their social similarity and evaluates their social trust,
strengthening the reliability between legitimate devices and their resilience
against the interaction of Sybil attackers. NS-3 Simulations show the ELECTRON
performance under Sybil attacks on several IoT communities so that it has
gotten to detect more than 90% of attackers in a scenario with 150 nodes into
offices, schools, gyms, and~parks communities, and in other scenarios for same
communities it achieved around of 90\% of detection. Furthermore, it provided
high accuracy, over 90-95%, and false positive rates closer to zero.
