 both &quot;TLS WWW Server Authentication&quot; and &quot;TLS Client Authentication&quot;, but a system administrator might only trust it for the former. An X.509 certificate extension exists that can record extended key usage information to supplement the purpose information described above. This extended mechanism is arbitrarily extensible and not well suited for a generic library API; applications that need to validate extended key usage information in certificates will need to define a custom &quot;purp