HTTP header insert with CN and for SHA1 thumbprint of the SSL certificate ?

when CLIENTSSL_CLIENTCERT priority 100 {
    if {[SSL::cert count] > 0} {
        set clientCert [X509::whole [SSL::cert 0]]
        set clientCertSubject [X509::subject [SSL::cert 0]]
        set clientCertHash [X509::hash [SSL::cert 0]]
        foreach field [ split $clientCertSubject ","] {
            if {$field starts_with "CN="} {
                set clientCommonName [getfield $field "=" 2]
            }
        }
    }
}
 
when HTTP_REQUEST {
    if {(info exists clientCert) && ($clientCert ne "")} {
        HTTP::header insert X-Client-Cert $clientCert
    }
 
    if {(info exists clientCommonName) && ($clientCommonName ne "")} {
        HTTP::header insert X-Client-CN $clientCommonName
    }
 
    if {(info exists clientCertHash) && ($clientCertHash ne "")} {
        HTTP::header insert X-Client-hash $clientCertHash
    }
}