openssl-ocsp, ocsp - Online Certificate Status Protocol utility
openssl ocsp [-help] [-out file] [-issuer file] [-cert file] [-serial n] [-signer file] [-signkey file] [-sign_other file] [-no_certs] [-req_text] [-resp_text] [-text] [-reqout file] [-respout file] [-reqin file] [-respin file] [-nonce] [-no_nonce] [-url URL] [-host host:port] [-header] [-path] [-CApath dir] [-CAfile file] [-no-CAfile] [-no-CApath] [-attime timestamp] [-check_ss_sig] [-crl_check] [-crl_check_all] [-explicit_policy] [-extended_crl] [-ignore_critical] [-inhibit_any] [-inhibit_map] [-no_check_time] [-partial_chain] [-policy arg] [-policy_check] [-policy_print] [-purpose purpose] [-suiteB_128] [-suiteB_128_only] [-suiteB_192] [-trusted_first] [-no_alt_chains] [-use_deltas] [-auth_level num] [-verify_depth num] [-verify_email email] [-verify_hostname hostname] [-verify_ip ip] [-verify_name name] [-x509_strict] [-VAfile file] [-validity_period n] [-status_age n] [-noverify] [-verify_other file] [-trust_other] [-no_intern] [-no_signature_verify] [-no_cert_verify] [-no_chain] [-no_cert_checks] [-no_explicit] [-port num] [-index file] [-CA file] [-rsigner file] [-rkey file] [-rother file] [-resp_no_certs] [-nmin n] [-ndays n] [-resp_key_id] [-nrequest n] [-md5|-sha1|...]
The Online Certificate Status Protocol (OCSP) enables applications to determine the (revocation) state of an identified certificate (RFC 2560).
The ocsp command performs many common OCSP tasks. It can be used to print out requests and responses, create requests and send queries to an OCSP responder and behave like a mini OCSP server itself.
This command operates as either a client or a server. The options are described below, divided into those two modes.
Print out a usage message.
specify output filename, default is standard output.
This specifies the current issuer certificate. This option can be used multiple times. The certificate specified in filename must be in PEM format. This option MUST come before any -cert options.
Add the certificate filename to the request. The issuer certificate is taken from the previous issuer option, or an error occurs if no issuer certificate is specified.
Same as the cert option except the certificate with serial number num is added to the request. The serial number is interpreted as a decimal integer unless preceded by 0x. Negative integers can also be specified by preceding the value by a - sign.
Sign the OCSP request using the certificate specified in the signer option and the private key specified by the signkey option. If the signkey option is not present then the private key is read from the same file as the certificate. If neither option is specified then the OCSP request is not signed.
Additional certificates to include in the signed request.
Add an OCSP nonce extension to a request or disable OCSP nonce addition. Normally if an OCSP request is input using the reqin option no nonce is added: using the nonce option will force addition of a nonce. If an OCSP request is being created (using cert and serial options) a nonce is automatically added specifying no_nonce overrides this.
print out the text form of the OCSP request, response or both respectively.
write out the DER encoded certificate request or response to file.
read OCSP request or response file from file. These option are ignored if OCSP request or response creation is implied by other options (for example with serial, cert and host options).
specify the responder URL. Both HTTP and HTTPS (SSL/TLS) URLs can be specified.
if the host option is present then the OCSP request is sent to the host hostname on port port. path specifies the HTTP path name to use or "/" by default. This is equivalent to specifying -url with scheme http:// and the given hostname, port, and pathname.
Adds the header name with the specified value to the OCSP request that is sent to the responder. This may be repeated.
connection timeout to the OCSP responder in seconds
file or pathname containing trusted CA certificates. These are used to verify the signature on the OCSP response.
Do not load the trusted CA certificates from the default file location
Do not load the trusted CA certificates from the default directory location
indexfile is a text index file in ca format containing certificate revocation information.
If the index option is specified the ocsp utility is in responder mode, otherwise it is in client mode. The request(s) the responder processes can be either specified on the command line (using issuer and serial options), supplied in a file (using the reqin option) or via external OCSP clients (if port or url is specified).
If the index option is present then the CA and rsigner options must also be present.
CA certificate corresponding to the revocation information in indexfile.
The certificate to sign OCSP responses with.
Additional certificates to include in the OCSP response.
Don't include any certificates in the OCSP response.
Identify the signer certificate using the key ID, default is to use the subject name.
The private key to sign OCSP responses with: if not present the file specified in the rsigner option is used.
Port to listen for OCSP requests on. The port may also be specified using the url option.
The OCSP server will exit after receiving number requests, default unlimited.
Number of minutes or days when fresh revocation information is available: used in the nextUpdate field. If neither option is present then the nextUpdate field is omitted meaning fresh revocation information is immediately available.
OCSP Response follows the rules specified in RFC2560.
Initially the OCSP responder certificate is located and the signature on the OCSP request checked using the responder certificate's public key.
Then a normal certificate verify is performed on the OCSP responder certificate building up a certificate chain in the process. The locations of the trusted certificates used to build the chain can be specified by the CAfile and CApath options or they will be looked for in the standard OpenSSL certificates directory.
If the initial verify fails then the OCSP verify process halts with an error.
Otherwise the issuing CA certificate in the request is compared to the OCSP responder certificate: if there is a match then the OCSP verify succeeds.
Otherwise the OCSP responder certificate's CA is checked against the issuing CA certificate in the request. If there is a match and the OCSPSigning extended key usage is present in the OCSP responder certificate then the OCSP verify succeeds.
Otherwise, if -no_explicit is not set the root CA of the OCSP responders CA is checked to see if it is trusted for OCSP signing. If it is the OCSP verify succeeds.
If none of these checks is successful then the OCSP verify fails.
What this effectively means if that if the OCSP responder certificate is authorised directly by the CA it is issuing revocation information about (and it is correctly configured) then verification will succeed.
If the OCSP responder is a "global responder" which can give details about multiple CAs and has its own separate certificate chain then its root CA can be trusted for OCSP signing. For example:
openssl x509 -in ocspCA.pem -addtrust OCSPSigning -out trustedCA.pem
Alternatively the responder certificate itself can be explicitly trusted with the -VAfile option.
As noted, most of the verify options are for testing or debugging purposes. Normally only the -CApath, -CAfile and (if the responder is a 'global VA') -VAfile options need to be used.
The OCSP server is only useful for test and demonstration purposes: it is not really usable as a full OCSP responder. It contains only a very simple HTTP request handling and can only handle the POST form of OCSP queries. It also handles requests serially meaning it cannot respond to new requests until it has processed the current one. The text index file format of revocation is also inefficient for large quantities of revocation data.
It is possible to run the ocsp application in responder mode via a CGI script using the reqin and respout options.
Create an OCSP request and write it to a file:
openssl ocsp -issuer issuer.pem -cert c1.pem -cert c2.pem -reqout req.der
Send a query to an OCSP responder with URL http://ocsp.myhost.com/ save the response to a file, print it out in text form, and verify the response:
openssl ocsp -issuer issuer.pem -cert c1.pem -cert c2.pem \
-url http://ocsp.myhost.com/ -resp_text -respout resp.der
Read in an OCSP response and print out text form:
openssl ocsp -respin resp.der -text -noverify
OCSP server on port 8888 using a standard ca configuration, and a separate responder certificate. All requests and responses are printed to a file.
openssl ocsp -index demoCA/index.txt -port 8888 -rsigner rcert.pem -CA demoCA/cacert.pem
-text -out log.txt
As above but exit after processing one request:
openssl ocsp -index demoCA/index.txt -port 8888 -rsigner rcert.pem -CA demoCA/cacert.pem
-nrequest 1
Query status information using an internally generated request:
openssl ocsp -index demoCA/index.txt -rsigner rcert.pem -CA demoCA/cacert.pem
-issuer demoCA/cacert.pem -serial 1
Query status information using request read from a file, and write the response to a second file.
openssl ocsp -index demoCA/index.txt -rsigner rcert.pem -CA demoCA/cacert.pem
-reqin req.der -respout resp.der
The -no_alt_chains options was first added to OpenSSL 1.1.0.
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