Due to the rapid spread of distributed energy resources, the demand for intermediary trading (i.e., brokerage) of surplus electricity for energy prosumers in electricity markets is significantly increasing. To support transparency of brokerage transactions in the trading process, various technologies such as blockchain can be applied to applications that require mutual trust between users in a trustless environment. Thus, this draft Recommendation provides a framework of trusted electricity brokerage for distributed energy resources taking into account the blockchain technology for trust provisioning in electricity markets. After introducing key characteristics, core technologies and service scenarios for trusted electricity brokerage with the necessity of the blockchain technology to ensure trust, this draft Recommendation mainly presents requirements, architecture overview specifying related interfaces and functional blocks for the blockchain enabled trusted electricity brokerage.