Provided by: gnutls-bin_3.5.18-1ubuntu1.6_amd64 
NAME
ocsptool - GnuTLS OCSP tool
SYNOPSIS
ocsptool [-flags] [-flag [value]] [--option-name[[=| ]value]]
All arguments must be options.
DESCRIPTION
Ocsptool is a program that can parse and print information about OCSP requests/responses, generate
requests and verify responses.
OPTIONS
-d number, --debug=number
Enable debugging. This option takes an integer number as its argument. The value of number is
constrained to being:
in the range 0 through 9999
Specifies the debug level.
-V, --verbose
More verbose output. This option may appear an unlimited number of times.
--infile=file
Input file.
--outfile=string
Output file.
--ask [=server name|url]
Ask an OCSP/HTTP server on a certificate validity. This option must appear in combination with
the following options: load-cert, load-issuer.
Connects to the specified HTTP OCSP server and queries on the validity of the loaded certificate.
-e, --verify-response
Verify response.
-i, --request-info
Print information on a OCSP request.
-j, --response-info
Print information on a OCSP response.
-q, --generate-request
Generate an OCSP request.
--nonce, --no-nonce
Use (or not) a nonce to OCSP request. The no-nonce form will disable the option.
--load-issuer=file
Read issuer certificate from file.
--load-cert=file
Read certificate to check from file.
--load-trust=file
Read OCSP trust anchors from file. This option must not appear in combination with any of the
following options: load-signer.
--load-signer=file
Read OCSP response signer from file. This option must not appear in combination with any of the
following options: load-trust.
--inder, --no-inder
Use DER format for input certificates and private keys. The no-inder form will disable the
option.
-Q file, --load-request=file
Read DER encoded OCSP request from file.
-S file, --load-response=file
Read DER encoded OCSP response from file.
--ignore-errors
Ignore any verification errors.
-h, --help
Display usage information and exit.
-!, --more-help
Pass the extended usage information through a pager.
-v [{v|c|n --version [{v|c|n}]}]
Output version of program and exit. The default mode is `v', a simple version. The `c' mode will
print copyright information and `n' will print the full copyright notice.
EXAMPLES
Print information about an OCSP request
To parse an OCSP request and print information about the content, the -i or --request-info parameter may
be used as follows. The -Q parameter specify the name of the file containing the OCSP request, and it
should contain the OCSP request in binary DER format.
$ ocsptool -i -Q ocsp-request.der
The input file may also be sent to standard input like this:
$ cat ocsp-request.der | ocsptool --request-info
Print information about an OCSP response
Similar to parsing OCSP requests, OCSP responses can be parsed using the -j or --response-info as
follows.
$ ocsptool -j -Q ocsp-response.der
$ cat ocsp-response.der | ocsptool --response-info
Generate an OCSP request
The -q or --generate-request parameters are used to generate an OCSP request. By default the OCSP
request is written to standard output in binary DER format, but can be stored in a file using --outfile.
To generate an OCSP request the issuer of the certificate to check needs to be specified with
--load-issuer and the certificate to check with --load-cert. By default PEM format is used for these
files, although --inder can be used to specify that the input files are in DER format.
$ ocsptool -q --load-issuer issuer.pem --load-cert client.pem --outfile ocsp-request.der
When generating OCSP requests, the tool will add an OCSP extension containing a nonce. This behaviour
can be disabled by specifying --no-nonce.
Verify signature in OCSP response
To verify the signature in an OCSP response the -e or --verify-response parameter is used. The tool will
read an OCSP response in DER format from standard input, or from the file specified by --load-response.
The OCSP response is verified against a set of trust anchors, which are specified using --load-trust.
The trust anchors are concatenated certificates in PEM format. The certificate that signed the OCSP
response needs to be in the set of trust anchors, or the issuer of the signer certificate needs to be in
the set of trust anchors and the OCSP Extended Key Usage bit has to be asserted in the signer
certificate.
$ ocsptool -e --load-trust issuer.pem --load-response ocsp-response.der
The tool will print status of verification.
Verify signature in OCSP response against given certificate
It is possible to override the normal trust logic if you know that a certain certificate is supposed to
have signed the OCSP response, and you want to use it to check the signature. This is achieved using
--load-signer instead of --load-trust. This will load one certificate and it will be used to verify the
signature in the OCSP response. It will not check the Extended Key Usage bit.
$ ocsptool -e --load-signer ocsp-signer.pem --load-response ocsp-response.der
This approach is normally only relevant in two situations. The first is when the OCSP response does not
contain a copy of the signer certificate, so the --load-trust code would fail. The second is if you want
to avoid the indirect mode where the OCSP response signer certificate is signed by a trust anchor.
Real-world example
Here is an example of how to generate an OCSP request for a certificate and to verify the response. For
illustration we'll use the blog.josefsson.org host, which (as of writing) uses a certificate from CACert.
First we'll use gnutls-cli to get a copy of the server certificate chain. The server is not required to
send this information, but this particular one is configured to do so.
$ echo | gnutls-cli -p 443 blog.josefsson.org --print-cert > chain.pem
Use a text editor on chain.pem to create three files for each separate certificates, called cert.pem for
the first certificate for the domain itself, secondly issuer.pem for the intermediate certificate and
root.pem for the final root certificate.
The domain certificate normally contains a pointer to where the OCSP responder is located, in the
Authority Information Access Information extension. For example, from certtool -i < cert.pem there is
this information:
Authority Information Access Information (not critical):
Access Method: 1.3.6.1.5.5.7.48.1 (id-ad-ocsp)
Access Location URI: http://ocsp.CAcert.org/
This means the CA support OCSP queries over HTTP. We are now ready to create a OCSP request for the
certificate.
$ ocsptool --ask ocsp.CAcert.org --load-issuer issuer.pem --load-cert cert.pem --outfile ocsp-response.der
The request is sent via HTTP to the OCSP server address specified. If the address is omitted ocsptool
will use the address stored in the certificate.
EXIT STATUS
One of the following exit values will be returned:
0 (EXIT_SUCCESS)
Successful program execution.
1 (EXIT_FAILURE)
The operation failed or the command syntax was not valid.
70 (EX_SOFTWARE)
libopts had an internal operational error. Please report it to autogen-
users@lists.sourceforge.net. Thank you.
SEE ALSO
certtool (1)
AUTHORS
Nikos Mavrogiannopoulos, Simon Josefsson and others; see /usr/share/doc/gnutls/AUTHORS for a complete
list.
COPYRIGHT
Copyright (C) 2000-2018 Free Software Foundation, and others all rights reserved. This program is
released under the terms of the GNU General Public License, version 3 or later.
BUGS
Please send bug reports to: bugs@gnutls.org
NOTES
This manual page was AutoGen-erated from the ocsptool option definitions.