In this article, we explain the Qualys SSL Labs methodology.
MRI OnLocation believes in measuring our security and certificate implementations against best practice however, this needs to be independently assessed. Among the many tests we run, we also include an independent test using the Qualys SSL Labs methodology.
Qualys SSL Labs approach consists of four steps:
- They first look at a certificate to verify that it is valid and trusted.
- They inspect server configuration in three categories:
Protocol support
Key exchange support
Cipher support - They combine the category scores into an overall score (expressed as a number between 0 and 100). A zero in any category will push the overall score to zero. Then, a letter grade is calculated, using the table below.
- They then apply a series of rules (documented in the Changes section) to handle some aspects of server configuration that cannot be expressed via numerical scoring. Most rules will reduce the grade (to A-, B, C, D, E, or F) if they encounter an unwanted feature. Some rules will increase the grade (to A+), to reward exceptional configurations.
You can view the current certificate rating here.