f7744b72_e__8_0_24____The_AJP_Connector__Description
[Attribute] clientCertProvider [Description] 
When client certificate information is presented in a form other than instances of java.security.cert.X509Certificate it needs to be converted before it can be used and this property controls which JSSE provider is used to perform the conversion. For example it is used with the AJP connectors, the HTTP APR connector and with the org.apache.catalina.valves.SSLValve.If not specified, the default provider will be used.
Apache Tomcat 8 Configuration Reference (8.0.24) - The AJP Connector