Xinghuo Blockchain Infrastructure Facility Core，referred to as BIF-Core，is a licensed public blockchain built by China Academy of Information and Communications Technology based on blockchain technology，and is the key technology to realize Xinghuo BIF-core，a national blockchain and Industrial Internet collaborative innovation new infrastructure. BIF Core has built based on BID （Blockchain based IDentifier），which provides basic services such as ID registration resolution and digital identity for people，enterprises，devices，and digital objects. The tamper proof storage provided by BIF -core and the trusted execution provided by smart contracts，combined with the distributed system BID are very suitable for trusted certificate systems. This article describes a trusted digital certificate system and protocol specification running on the BIF-core，based on the Starfire BID system.