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
49 to an OCSP responder and behave like a mini OCSP server itself.
51 =head1 OCSP CLIENT OPTIONS
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, response 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 response: this option can be used to supply the necessary
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 responder 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 responses it will normally only be used for testing purposes.
159 =item B<-no_cert_verify>
161 don't verify the OCSP response 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 necessary 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 SERVER OPTIONS
198 =item B<-index indexfile>
200 B<indexfile> is a text index file in B<ca> format containing certificate revocation
203 If the B<index> option is specified the B<ocsp> utility is in responder mode, otherwise
204 it is in client mode. The request(s) the responder processes can be either specified on
205 the command line (using B<issuer> and B<serial> options), supplied in a file (using the
206 B<respin> option) or via external OCSP clients (if B<port> or B<url> is specified).
208 If the B<index> option is present then the B<CA> and B<rsigner> options must also be
213 CA certificate corresponding to the revocation information in B<indexfile>.
215 =item B<-rsigner file>
217 The certificate to sign OCSP responses with.
219 =item B<-rother file>
221 Additional certificates to include in the OCSP response.
223 =item B<-resp_no_certs>
225 Don't include any certificates in the OCSP response.
227 =item B<-resp_key_id>
229 Identify the signer certificate using the key ID, default is to use the subject name.
233 The private key to sign OCSP responses with: if not present the file specified in the
234 B<rsigner> option is used.
236 =item B<-port portnum>
238 Port to listen for OCSP requests on. The port may also be specified using the B<url>
241 =item B<-nrequest number>
243 The OCSP server will exit after receiving B<number> requests, default unlimited.
245 =item B<-nmin minutes>, B<-ndays days>
247 Number of minutes or days when fresh revocation information is available: used in the
248 B<nextUpdate> field. If neither option is present then the B<nextUpdate> field is
249 omitted meaning fresh revocation information is immediately available.
253 =head1 OCSP Response verification.
255 OCSP Response follows the rules specified in RFC2560.
257 Initially the OCSP responder certificate is located and the signature on
258 the OCSP request checked using the responder certificate's public key.
260 Then a normal certificate verify is performed on the OCSP responder certificate
261 building up a certificate chain in the process. The locations of the trusted
262 certificates used to build the chain can be specified by the B<CAfile>
263 and B<CApath> options or they will be looked for in the standard OpenSSL
264 certificates directory.
266 If the initial verify fails then the OCSP verify process halts with an
269 Otherwise the issuing CA certificate in the request is compared to the OCSP
270 responder certificate: if there is a match then the OCSP verify succeeds.
272 Otherwise the OCSP responder certificate's CA is checked against the issuing
273 CA certificate in the request. If there is a match and the OCSPSigning
274 extended key usage is present in the OCSP responder certificate then the
275 OCSP verify succeeds.
277 Otherwise the root CA of the OCSP responders CA is checked to see if it
278 is trusted for OCSP signing. If it is the OCSP verify succeeds.
280 If none of these checks is successful then the OCSP verify fails.
282 What this effectively means if that if the OCSP responder certificate is
283 authorised directly by the CA it is issuing revocation information about
284 (and it is correctly configured) then verification will succeed.
286 If the OCSP responder is a "global responder" which can give details about
287 multiple CAs and has its own separate certificate chain then its root
288 CA can be trusted for OCSP signing. For example:
290 openssl x509 -in ocspCA.pem -addtrust OCSPSigning -out trustedCA.pem
292 Alternatively the responder certificate itself can be explicitly trusted
293 with the B<-VAfile> option.
297 As noted, most of the verify options are for testing or debugging purposes.
298 Normally only the B<-CApath>, B<-CAfile> and (if the responder is a 'global
299 VA') B<-VAfile> options need to be used.
301 The OCSP server is only useful for test and demonstration purposes: it is
302 not really usable as a full OCSP responder. It contains only a very
303 simple HTTP request handling and can only handle the POST form of OCSP
304 queries. It also handles requests serially meaning it cannot respond to
305 new requests until it has processed the current one. The text index file
306 format of revocation is also inefficient for large quantities of revocation
309 It is possible to run the B<ocsp> application in responder mode via a CGI
310 script using the B<respin> and B<respout> options.
314 Create an OCSP request and write it to a file:
316 openssl ocsp -issuer issuer.pem -cert c1.pem -cert c2.pem -reqout req.der
318 Send a query to an OCSP responder with URL http://ocsp.myhost.com/ save the
319 response to a file and print it out in text form
321 openssl ocsp -issuer issuer.pem -cert c1.pem -cert c2.pem \
322 -url http://ocsp.myhost.com/ -resp_text -respout resp.der
324 Read in an OCSP response and print out text form:
326 openssl ocsp -respin resp.der -text
328 OCSP server on port 8888 using a standard B<ca> configuration, and a separate
329 responder certificate. All requests and responses are printed to a file.
331 openssl ocsp -index demoCA/index.txt -port 8888 -rsigner rcert.pem -CA demoCA/cacert.pem
334 As above but exit after processing one request:
336 openssl ocsp -index demoCA/index.txt -port 8888 -rsigner rcert.pem -CA demoCA/cacert.pem
339 Query status information using internally generated request:
341 openssl ocsp -index demoCA/index.txt -rsigner rcert.pem -CA demoCA/cacert.pem
342 -issuer demoCA/cacert.pem -serial 1
344 Query status information using request read from a file, write response to a
347 openssl ocsp -index demoCA/index.txt -rsigner rcert.pem -CA demoCA/cacert.pem
348 -reqin req.der -respout resp.der