+Moreover, according to RFC 4210 section 5.3.2, if the message protection is
+PBM-based then any certificates in the caPubs field are added to the list of
+trusted certificates (if set via L<OSSL_CMP_CTX_set0_trustedStore(3)>).
+This way these certs are available for validating subsequent messages in the
+same context and could apply to any Polling Response (pollRep), error, or PKI
+Confirmation (PKIConf) messages following in the same or future transactions.
+