Nowadays the continuous increase in the world energy consumption is bringing to the attention of everyone the problem of sustainability, since this demand still relies mainly on non-renewable energy sources. In this context, smart energy grids are emerging, as they allow to better exploit the distributed energy resources (DER), which are based instead on a renewable and thus more sustainable energy production. The thesis points out the front-running vulnerabilities and proposes prevention strategies to mitigate possible attacks in a blockchain-based trading system for electricity in prosumer communities. An investigation of the blockchain front-running literature is presented in order to define the problem in the analysed project.