ca - sample minimal CA application
SYNOPSIS
openssl ca [-verbose] [-config filename] [-name section]
[-gencrl] [-revoke file] [-crldays days] [-crlhours hours]
[-crlexts section] [-startdate date] [-enddate date]
[-days arg] [-md arg] [-policy arg] [-keyfile arg] [-key
arg] [-passin arg] [-cert file] [-in file] [-out file]
[-notext] [-outdir dir] [-infiles] [-spkac file] [-ss_cert
file] [-preserveDN] [-batch] [-msie_hack] [-extensions
section]
DESCRIPTION
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.
-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.
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 PASS PHRASE ARGUMENTS
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 POLICY FORMAT 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
-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 options for ca are contained in the ca section of the
configuration file. Many of these are identical to command
line options. Where the option is present in the
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 OBJECT
IDENTIFIERS. 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
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 POLICY FORMAT
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
'.'.
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 ]
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
policy = policy_any # default policy
[ policy_any ]
countryName = supplied
stateOrProvinceName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
WARNINGS
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
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.
req(1), spkac(1), x509(1), CA.pl(1), config(5)
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