The ca command is a minimal CA application. It can be used
to sign certificate requests in a variety of forms and generate
CRLs it also maintains a text database of issued certificates
and their status.
The options descriptions will be divided into each purpose.
CA OPTIONS
-config filename
specifies the configuration file to use.
-name section
specifies the configuration file section to use (overrides
default_ca in the ca section).
-in filename
an input filename containing a single certificate request to be
signed by the CA.
-ss_cert filename
a single self signed certificate to be signed by the CA.
-spkac filename
a file containing a single Netscape signed public key and challenge
and additional field values to be signed by the CA. See the NOTES
section for information on the required format.
-infiles
if present this should be the last option, all subsequent arguments
are assumed to the the names of files containing certificate requests.
-out filename
the output file to output certificates to. The default is standard
output. The certificate details will also be printed out to this
file.
-outdir directory
the directory to output certificates to. The certificate will be
written to a filename consisting of the serial number in hex with
``.pem'' appended.
-cert
the CA certificate file.
-keyfile filename
the private key to sign requests with.
-key password
the password used to encrypt the private key. Since on some
systems the command line arguments are visible (e.g. Unix with
the `ps' utility) this option should be used with caution.
-passin arg
the key password source. For more information about the format of arg
see the PASSPHRASEARGUMENTS section in openssl(1).
=item -verbose
this prints extra details about the operations being performed.
-notext
don't output the text form of a certificate to the output file.
-startdate date
this allows the start date to be explicitly set. The format of the
date is YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure).
-enddate date
this allows the expiry date to be explicitly set. The format of the
date is YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure).
-days arg
the number of days to certify the certificate for.
-md alg
the message digest to use. Possible values include md5, sha1 and mdc2.
This option also applies to CRLs.
-policy arg
this option defines the CA ``policy'' to use. This is a section in
the configuration file which decides which fields should be mandatory
or match the CA certificate. Check out the POLICYFORMAT section
for more information.
-msie_hack
this is a legacy option to make ca work with very old versions of
the IE certificate enrollment control ``certenr3''. It used UniversalStrings
for almost everything. Since the old control has various security bugs
its use is strongly discouraged. The newer control ``Xenroll'' does not
need this option.
-preserveDN
Normally the DN order of a certificate is the same as the order of the
fields in the relevant policy section. When this option is set the order
is the same as the request. This is largely for compatibility with the
older IE enrollment control which would only accept certificates if their
DNs match the order of the request. This is not needed for Xenroll.
-batch
this sets the batch mode. In this mode no questions will be asked
and all certificates will be certified automatically.
-extensions section
the section of the configuration file containing certificate extensions
to be added when a certificate is issued. If no extension section is
present then a V1 certificate is created. If the extension section
is present (even if it is empty) then a V3 certificate is created.
CRL OPTIONS
-gencrl
this option generates a CRL based on information in the index file.
-crldays num
the number of days before the next CRL is due. That is the days from
now to place in the CRL nextUpdate field.
-crlhours num
the number of hours before the next CRL is due.
-revoke filename
a filename containing a certificate to revoke.
-crlexts section
the section of the configuration file containing CRL extensions to
include. If no CRL extension section is present then a V1 CRL is
created, if the CRL extension section is present (even if it is
empty) then a V2 CRL is created. The CRL extensions specified are
CRL extensions and not CRL entry extensions. It should be noted
that some software (for example Netscape) can't handle V2 CRLs.
CONFIGURATION FILE OPTIONS
The section of the configuration file containing options for ca
is found as follows: If the -name command line option is used,
then it names the section to be used. Otherwise the section to
be used must be named in the default_ca option of the ca section
of the configuration file (or in the default section of the
configuration file). Besides default_ca, the following options are
read directly from the ca section:
RANDFILE
preserve
msie_hack
With the exception of RANDFILE, this is probably a bug and may
change in future releases.
Many of the configuration file options are identical to command line
options. Where the option is present in the configuration file
and the command line the command line value is used. Where an
option is described as mandatory then it must be present in
the configuration file or the command line equivalent (if
any) used.
oid_file
This specifies a file containing additional OBJECTIDENTIFIERS.
Each line of the file should consist of the numerical form of the
object identifier followed by white space then the short name followed
by white space and finally the long name.
oid_section
This specifies a section in the configuration file containing extra
object identifiers. Each line should consist of the short name of the
object identifier followed by = and the numerical form. The short
and long names are the same when this option is used.
new_certs_dir
the same as the -outdir command line option. It specifies
the directory where new certificates will be placed. Mandatory.
certificate
the same as -cert. It gives the file containing the CA
certificate. Mandatory.
private_key
same as the -keyfile option. The file containing the
CA private key. Mandatory.
RANDFILE
a file used to read and write random number seed information, or
an EGD socket (see RAND_egd(3)).
default_days
the same as the -days option. The number of days to certify
a certificate for.
default_startdate
the same as the -startdate option. The start date to certify
a certificate for. If not set the current time is used.
default_enddate
the same as the -enddate option. Either this option or
default_days (or the command line equivalents) must be
present.
default_crl_hours default_crl_days
the same as the -crlhours and the -crldays options. These
will only be used if neither command line option is present. At
least one of these must be present to generate a CRL.
default_md
the same as the -md option. The message digest to use. Mandatory.
database
the text database file to use. Mandatory. This file must be present
though initially it will be empty.
serialfile
a text file containing the next serial number to use in hex. Mandatory.
This file must be present and contain a valid serial number.
x509_extensions
the same as -extensions.
crl_extensions
the same as -crlexts.
preserve
the same as -preserveDN
msie_hack
the same as -msie_hack
policy
the same as -policy. Mandatory. See the POLICYFORMAT section
for more information.
POLICY FORMAT
The policy section consists of a set of variables corresponding to
certificate DN fields. If the value is ``match'' then the field value
must match the same field in the CA certificate. If the value is
``supplied'' then it must be present. If the value is ``optional'' then
it may be present. Any fields not mentioned in the policy section
are silently deleted, unless the -preserveDN option is set but
this can be regarded more of a quirk than intended behaviour.
SPKAC FORMAT
The input to the -spkac command line option is a Netscape
signed public key and challenge. This will usually come from
the KEYGEN tag in an HTML form to create a new private key.
It is however possible to create SPKACs using the spkac utility.
The file should contain the variable SPKAC set to the value of
the SPKAC and also the required DN components as name value pairs.
If you need to include the same component twice then it can be
preceded by a number and a `.'.
EXAMPLES
Note: these examples assume that the ca directory structure is
already set up and the relevant files already exist. This usually
involves creating a CA certificate and private key with req, a
serial number file and an empty index file and placing them in
the relevant directories.
To use the sample configuration file below the directories demoCA,
demoCA/private and demoCA/newcerts would be created. The CA
certificate would be copied to demoCA/cacert.pem and its private
key to demoCA/private/cakey.pem. A file demoCA/serial would be
created containing for example ``01'' and the empty index file
demoCA/index.txt.
Sign a certificate request:
openssl ca -in req.pem -out newcert.pem
Sign a certificate request, using CA extensions:
openssl ca -in req.pem -extensions v3_ca -out newcert.pem
Generate a CRL
openssl ca -gencrl -out crl.pem
Sign several requests:
openssl ca -infiles req1.pem req2.pem req3.pem
Certify a Netscape SPKAC:
openssl ca -spkac spkac.txt
A sample SPKAC file (the SPKAC line has been truncated for clarity):
SPKAC=MIG0MGAwXDANBgkqhkiG9w0BAQEFAANLADBIAkEAn7PDhCeV/xIxUg8V70YRxK2A5
CN=Steve Test
emailAddress=steve@openssl.org
0.OU=OpenSSL Group
1.OU=Another Group
A sample configuration file with the relevant sections for ca:
[ ca ]
default_ca = CA_default # The default ca section
[ CA_default ]
dir = ./demoCA # top dir
database = $dir/index.txt # index file.
new_certs_dir = $dir/newcerts # new certs dir
certificate = $dir/cacert.pem # The CA cert
serial = $dir/serial # serial no file
private_key = $dir/private/cakey.pem# CA private key
RANDFILE = $dir/private/.rand # random number file
default_days = 365 # how long to certify for
default_crl_days= 30 # how long before next CRL
default_md = md5 # md to use
The ca command is quirky and at times downright unfriendly.
The ca utility was originally meant as an example of how to do things
in a CA. It was not supposed be be used as a full blown CA itself:
nevertheless some people are using it for this purpose.
The ca command is effectively a single user command: no locking is
done on the various files and attempts to run more than one ca command
on the same database can have unpredictable results.
FILES
Note: the location of all files can change either by compile time options,
configuration file entries, environment variables or command line options.
The values below reflect the default values.
/usr/local/ssl/lib/openssl.cnf - master configuration file
./demoCA - main CA directory
./demoCA/cacert.pem - CA certificate
./demoCA/private/cakey.pem - CA private key
./demoCA/serial - CA serial number file
./demoCA/serial.old - CA serial number backup file
./demoCA/index.txt - CA text database file
./demoCA/index.txt.old - CA text database backup file
./demoCA/certs - certificate output file
./demoCA/.rnd - CA random seed information
ENVIRONMENT VARIABLES
OPENSSL_CONF reflects the location of master configuration file it can
be overridden by the -config command line option.
RESTRICTIONS
The text database index file is a critical part of the process and
if corrupted it can be difficult to fix. It is theoretically possible
to rebuild the index file from all the issued certificates and a current
CRL: however there is no option to do this.
CRL entry extensions cannot currently be created: only CRL extensions
can be added.
V2 CRL features like delta CRL support and CRL numbers are not currently
supported.
Although several requests can be input and handled at once it is only
possible to include one SPKAC or self signed certificate.
BUGS
The use of an in memory text database can cause problems when large
numbers of certificates are present because, as the name implies
the database has to be kept in memory.
Certificate request extensions are ignored: some kind of ``policy'' should
be included to use certain static extensions and certain extensions
from the request.
It is not possible to certify two certificates with the same DN: this
is a side effect of how the text database is indexed and it cannot easily
be fixed without introducing other problems. Some S/MIME clients can use
two certificates with the same DN for separate signing and encryption
keys.
The ca command really needs rewriting or the required functionality
exposed at either a command or interface level so a more friendly utility
(perl script or GUI) can handle things properly. The scripts CA.sh and
CA.pl help a little but not very much.
Any fields in a request that are not present in a policy are silently
deleted. This does not happen if the -preserveDN option is used but
the extra fields are not displayed when the user is asked to certify
a request. The behaviour should be more friendly and configurable.
Cancelling some commands by refusing to certify a certificate can
create an empty file.
