+Print out a usage message.
+
+=item B<-ignore_critical>
+
+Normally if an unhandled critical extension is present which is not
+supported by OpenSSL the certificate is rejected (as required by RFC5280).
+If this option is set critical extensions are ignored.
+
+=item B<-inhibit_any>
+
+Set policy variable inhibit-any-policy (see RFC5280).
+
+=item B<-inhibit_map>
+
+Set policy variable inhibit-policy-mapping (see RFC5280).
+
+=item B<-issuer_checks>
+
+Print out diagnostics relating to searches for the issuer certificate of the
+current certificate. This shows why each candidate issuer certificate was
+rejected. The presence of rejection messages does not itself imply that
+anything is wrong; during the normal verification process, several
+rejections may take place.
+
+=item B<-partial_chain>
+
+Allow partial certificate chain if at least one certificate is in trusted store.
+
+=item B<-policy arg>
+
+Enable policy processing and add B<arg> to the user-initial-policy-set (see
+RFC5280). The policy B<arg> can be an object name an OID in numeric form.
+This argument can appear more than once.
+
+=item B<-policy_check>
+
+Enables certificate policy processing.
+
+=item B<-policy_print>
+
+Print out diagnostics related to policy processing.
+
+=item B<-purpose purpose>
+
+The intended use for the certificate. If this option is not specified,
+B<verify> will not consider certificate purpose during chain verification.
+Currently accepted uses are B<sslclient>, B<sslserver>, B<nssslserver>,
+B<smimesign>, B<smimeencrypt>. See the B<VERIFY OPERATION> section for more
+information.
+
+=item B<-suiteB_128_only>, B<-suiteB_128>, B<-suiteB_192>
+
+enable the Suite B mode operation at 128 bit Level of Security, 128 bit or
+192 bit, or only 192 bit Level of Security respectively.
+See RFC6460 for details. In particular the supported signature algorithms are
+reduced to support only ECDSA and SHA256 or SHA384 and only the elliptic curves
+P-256 and P-384.
+
+=item B<-trusted_first>
+
+Use certificates in CA file or CA directory before certificates in untrusted
+file when building the trust chain to verify certificates.
+This is mainly useful in environments with Bridge CA or Cross-Certified CAs.
+
+=item B<-untrusted file>
+
+A file of untrusted certificates. The file should contain multiple certificates
+in PEM format concatenated together.
+
+=item B<-use_deltas>
+
+Enable support for delta CRLs.