X509_find_by_subject
return X509_find_by_subject(certs, id->value.byName);
signer = X509_find_by_subject(req->optionalSignature->certs, nm);
signer = X509_find_by_subject(certs, nm);
X509 *X509_find_by_subject(STACK_OF(X509) *sk,X509_NAME *name);
issuer = X509_find_by_subject(extra_certs, issuer_name);