5 ocsp - Online Certificate Status Protocol utility
23 [B<-url responder_url>]
29 [B<-verify_certs file>]
37 [B<-validity_period nsec>]
42 B<WARNING: this documentation is preliminary and subject to change.>
44 The Online Certificate Status Protocol (OCSP) enables applications to
45 determine the (revocation) state of an identified certificate (RFC 2560).
47 The B<ocsp> command performs many common OCSP tasks. It can be used
48 to print out requests and responses, create requests and send queries
55 =item B<-out filename>
57 specify output filename, default is standard output.
59 =item B<-issuer filename>
61 This specifies the current issuer certificate. This option can be used
62 multiple times. The certificate specified in B<filename> must be in
65 =item B<-cert filename>
67 Add the certificate B<filename> to the request. The issuer certificate
68 is taken from the previous B<issuer> option, or an error occurs if no
69 issuer certificate is specified.
73 Same as the B<cert> option except the certificate with serial number
74 B<num> is added to the request. The serial number is interpreted as a
75 decimal integer unless preceded by B<0x>. Negative integers can also
76 be specified by preceding the value by a B<-> sign.
78 =item B<-signer filename>, B<-signkey filename>
80 Sign the OCSP request using the certificate specified in the B<signer>
81 option and the private key specified by the B<signkey> option. If
82 the B<signkey> option is not present then the private key is read
83 from the same file as the certificate. If neither option is specified then
84 the OCSP request is not signed.
86 =item B<-nonce>, B<-no_nonce>
88 Add an OCSP nonce extension to a request or disable OCSP nonce addition.
89 Normally if an OCSP request is input using the B<respin> option no
90 nonce is added: using the B<nonce> option will force addition of a nonce.
91 If an OCSP request is being created (using B<cert> and B<serial> options)
92 a nonce is automatically added specifying B<no_nonce> overrides this.
94 =item B<-req_text>, B<-resp_text>, B<-text>
96 print out the text form of the OCSP request, reponse or both respectively.
98 =item B<-reqout file>, B<-respout file>
100 write out the DER encoded certificate request or response to B<file>.
102 =item B<-reqin file>, B<-respin file>
104 read OCSP request or response file from B<file>. These option are ignored
105 if OCSP request or response creation is implied by other options (for example
106 with B<serial>, B<cert> and B<host> options).
108 =item B<-url responder_url>
110 specify the responder URL. Both HTTP and HTTPS (SSL/TLS) URLs can be specified.
112 =item B<-host hostname:port>, B<-path pathname>
114 if the B<host> option is present then the OCSP request is sent to the host
115 B<hostname> on port B<port>. B<path> specifies the HTTP path name to use
118 =item B<-CAfile file>, B<-CApath pathname>
120 file or pathname containing trusted CA certificates. These are used to verify
121 the signature on the OCSP response.
123 =item B<-verify_certs file>
125 file containing additional certificates to search when attempting to locate
126 the OCSP response signing certificate. Some responders omit the actual signer's
127 certificate from the reponse: this option can be used to supply the neccesary
128 certificate in such cases.
130 =item B<-trust_other>
132 the certificates specified by the B<-verify_certs> option should be explicitly
133 trusted and no additional checks will be performed on them. This is useful
134 when the complete reponder certificate chain is not available or trusting a
135 root CA is not appropriate.
137 =item B<-VAfile file>
139 file containing explicitly trusted responder certificates. Equivalent to the
140 B<-verify_certs> and B<-trust_other> options.
144 don't attempt to verify the OCSP response signature or the nonce values. This
145 option will normally only be used for debugging since it disables all verification
146 of the responders certificate.
150 ignore certificates contained in the OCSP response when searching for the
151 signers certificate. With this option the signers certificate must be specified
152 with either the B<-verify_certs> or B<-VAfile> options.
154 =item B<-no_sig_verify>
156 don't check the signature on the OCSP response. Since this option tolerates invalid
157 signatures on OCSP respondes it will normally only be used for testing purposes.
159 =item B<-no_cert_verify>
161 don't verify the OCSP reponse signers certificate at all. Since this option allows
162 the OCSP response to be signed by any certificate it should only be used for
167 do not use certificates in the response as additional untrusted CA
170 =item B<-no_cert_checks>
172 don't perform any additional checks on the OCSP response signers certificate.
173 That is do not make any checks to see if the signers certificate is authorised
174 to provide the neccessary status information: as a result this option should
175 only be used for testing purposes.
177 =item B<-validity_period nsec>, B<-status_age age>
179 these options specify the range of times, in seconds, which will be tolerated
180 in an OCSP response. Each certificate status response includes a B<notBefore> time and
181 an optional B<notAfter> time. The current time should fall between these two values, but
182 the interval between the two times may be only a few seconds. In practice the OCSP
183 responder and clients clocks may not be precisely synchronised and so such a check
184 may fail. To avoid this the B<-validity_period> option can be used to specify an
185 acceptable error range in seconds, the default value is 5 minutes.
187 If the B<notAfter> time is omitted from a response then this means that new status
188 information is immediately available. In this case the age of the B<notBefore> field
189 is checked to see it is not older than B<age> seconds old. By default this additional
190 check is not performed.
194 =head1 OCSP Response verification.
196 OCSP Response follows the rules specified in RFC2560.
198 Initially the OCSP responder certificate is located and the signature on
199 the OCSP request checked using the reponder certificate's public key.
201 Then a normal certificate verify is performed on the OCSP responder certificate
202 building up a certificate chain in the process. The locations of the trusted
203 certificates used to build the chain can be specified by the B<CAfile>
204 and B<CApath> options or they will be looked for in the standard OpenSSL
205 certificates directory.
207 If the initial verify fails then the OCSP verify process halts with an
210 Otherwise the issuing CA certificate in the request is compared to the OCSP
211 responder certificate: if there is a match then the OCSP verify succeeds.
213 Otherwise the OCSP responder certificate's CA is checked against the issuing
214 CA certificate in the request. If there is a match and the OCSPSigning
215 extended key usage is present in the OCSP responder certificate then the
216 OCSP verify succeeds.
218 Otherwise the root CA of the OCSP responders CA is checked to see if it
219 is trusted for OCSP signing. If it is the OCSP verify succeeds.
221 If none of these checks is successful then the OCSP verify fails.
223 What this effectively means if that if the OCSP responder certificate is
224 authorised directly by the CA it is issuing revocation information about
225 (and it is correctly configured) then verification will succeed.
227 If the OCSP responder is a "global responder" which can give details about
228 multiple CAs and has its own separate certificate chain then its root
229 CA can be trusted for OCSP signing. For example:
231 openssl x509 -in ocspCA.pem -addtrust OCSPSigning -out trustedCA.pem
233 Alternatively the responder certificate itself can be explicitly trusted
234 with the B<-VAfile> option.
238 As noted, most of the verify options are for testing or debugging purposes.
239 Normally only the B<-CApath>, B<-CAfile> and (if the responder is a 'global
240 VA') B<-VAfile> options need to be used.
244 Create an OCSP request and write it to a file:
246 openssl ocsp -issuer issuer.pem -cert c1.pem -cert c2.pem -reqout req.der
248 Send a query an OCSP responder with URL http://ocsp.myhost.com/ save the
249 response to a file and print it out in text form
251 openssl ocsp -issuer issuer.pem -cert c1.pem -cert c2.pem \
252 -url http://ocsp.myhost.com/ -resp_text -respout resp.der
254 Read in an OCSP response and print out text form:
256 openssl ocsp -respin resp.der -text