The checking tool provided by the certification authority gives your domain an evaluation rating level between A and F. The analysis includes the server configurations for three categories: protocol support, support for exchanging public keys, and encryption support. Each of these categories is graded and contributes to an overall evaluation score between 0 and 100. Each evaluation rating corresponds to a score range (e.g. <20 for F, >=80 for A). Certificates that are not trusted will be awarded a T.