sig
val kp_server_auth : Netx509.oid
val kp_client_auth : Netx509.oid
val kp_code_signing : Netx509.oid
val kp_email_protection : Netx509.oid
val kp_time_stamping : Netx509.oid
val kp_ocsp_signing : Netx509.oid
val ext_key_purposes :
(Netx509.oid * Netx509.ext_key_usage_flag * string) list
end