Provided by: openssl_1.1.1f-1ubuntu2.24_amd64 
NAME
openssl-ca, ca - sample minimal CA application
SYNOPSIS
openssl ca [-help] [-verbose] [-config filename] [-name section] [-gencrl] [-revoke file] [-valid file]
[-status serial] [-updatedb] [-crl_reason reason] [-crl_hold instruction] [-crl_compromise time]
[-crl_CA_compromise time] [-crldays days] [-crlhours hours] [-crlexts section] [-startdate date]
[-enddate date] [-days arg] [-md arg] [-policy arg] [-keyfile arg] [-keyform PEM|DER] [-key arg] [-passin
arg] [-cert file] [-selfsign] [-in file] [-out file] [-notext] [-outdir dir] [-infiles] [-spkac file]
[-ss_cert file] [-preserveDN] [-noemailDN] [-batch] [-msie_hack] [-extensions section] [-extfile section]
[-engine id] [-subj arg] [-utf8] [-sigopt nm:v] [-create_serial] [-rand_serial] [-multivalue-rdn] [-rand
file...] [-writerand file]
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.
OPTIONS
-help
Print out a usage message.
-verbose
This prints extra details about the operations being performed.
-config filename
Specifies the configuration file to use. Optional; for a description of the default value, see
"COMMAND SUMMARY" in openssl(1).
-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 SPKAC FORMAT section for information on the required input and output
format.
-infiles
If present this should be the last option, all subsequent arguments are taken as 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 in PEM format (except that -spkac outputs DER format).
-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.
-keyform PEM|DER
The format of the data in the private key file. The default is PEM.
-sigopt nm:v
Pass options to the signature algorithm during sign or verify operations. Names and values of these
options are algorithm-specific.
-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.
-selfsign
Indicates the issued certificates are to be signed with the key the certificate requests were signed
with (given with -keyfile). Certificate requests signed with a different key are ignored. If
-spkac, -ss_cert or -gencrl are given, -selfsign is ignored.
A consequence of using -selfsign is that the self-signed certificate appears among the entries in the
certificate database (see the configuration option database), and uses the same serial number counter
as all other certificates sign with the self-signed certificate.
-passin arg
The key password source. For more information about the format of arg see the PASS PHRASE ARGUMENTS
section in openssl(1).
-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), or YYYYMMDDHHMMSSZ (the same as an ASN1 GeneralizedTime structure). In
both formats, seconds SS and timezone Z must be present.
-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), or YYYYMMDDHHMMSSZ (the same as an ASN1 GeneralizedTime structure). In
both formats, seconds SS and timezone Z must be present.
-days arg
The number of days to certify the certificate for.
-md alg
The message digest to use. Any digest supported by the OpenSSL dgst command can be used. For signing
algorithms that do not support a digest (i.e. Ed25519 and Ed448) any message digest that is set is
ignored. 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 deprecated 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.
-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.
-noemailDN
The DN of a certificate can contain the EMAIL field if present in the request DN, however it is good
policy just having the e-mail set into the altName extension of the certificate. When this option is
set the EMAIL field is removed from the certificate' subject and set only in the, eventually present,
extensions. The email_in_dn keyword can be used in the configuration file to enable this behaviour.
-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 (defaults to x509_extensions unless the -extfile option is used). 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. See the x509v3_config(5) manual page for
details of the extension section format.
-extfile file
An additional configuration file to read certificate extensions from (using the default section
unless the -extensions option is also used).
-engine id
Specifying an engine (by its unique id string) will cause ca to attempt to obtain a functional
reference to the specified engine, thus initialising it if needed. The engine will then be set as the
default for all available algorithms.
-subj arg
Supersedes subject name given in the request. The arg must be formatted as
/type0=value0/type1=value1/type2=.... Keyword characters may be escaped by \ (backslash), and
whitespace is retained. Empty values are permitted, but the corresponding type will not be included
in the resulting certificate.
-utf8
This option causes field values to be interpreted as UTF8 strings, by default they are interpreted as
ASCII. This means that the field values, whether prompted from a terminal or obtained from a
configuration file, must be valid UTF8 strings.
-create_serial
If reading serial from the text file as specified in the configuration fails, specifying this option
creates a new random serial to be used as next serial number. To get random serial numbers, use the
-rand_serial flag instead; this should only be used for simple error-recovery.
-rand_serial
Generate a large random number to use as the serial number. This overrides any option or
configuration to use a serial number file.
-multivalue-rdn
This option causes the -subj argument to be interpreted with full support for multivalued RDNs.
Example:
/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe
If -multi-rdn is not used then the UID value is 123456+CN=John Doe.
-rand file...
A file or files containing random data used to seed the random number generator. Multiple files can
be specified separated by an OS-dependent character. The separator is ; for MS-Windows, , for
OpenVMS, and : for all others.
[-writerand file]
Writes random data to the specified file upon exit. This can be used with a subsequent -rand flag.
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.
-valid filename
A filename containing a certificate to add a Valid certificate entry.
-status serial
Displays the revocation status of the certificate with the specified serial number and exits.
-updatedb
Updates the database index to purge expired certificates.
-crl_reason reason
Revocation reason, where reason is one of: unspecified, keyCompromise, CACompromise,
affiliationChanged, superseded, cessationOfOperation, certificateHold or removeFromCRL. The matching
of reason is case insensitive. Setting any revocation reason will make the CRL v2.
In practice removeFromCRL is not particularly useful because it is only used in delta CRLs which are
not currently implemented.
-crl_hold instruction
This sets the CRL revocation reason code to certificateHold and the hold instruction to instruction
which must be an OID. Although any OID can be used only holdInstructionNone (the use of which is
discouraged by RFC2459) holdInstructionCallIssuer or holdInstructionReject will normally be used.
-crl_compromise time
This sets the revocation reason to keyCompromise and the compromise time to time. time should be in
GeneralizedTime format that is YYYYMMDDHHMMSSZ.
-crl_CA_compromise time
This is the same as crl_compromise except the revocation reason is set to CACompromise.
-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. See
x509v3_config(5) manual page for details of the extension section format.
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 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
At startup the specified file is loaded into the random number generator, and at exit 256 bytes will
be written to it.
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. Mandatory except where the signing algorithm does not require a digest
(i.e. Ed25519 and Ed448).
database
The text database file to use. Mandatory. This file must be present though initially it will be
empty.
unique_subject
If the value yes is given, the valid certificate entries in the database must have unique subjects.
if the value no is given, several valid certificate entries may have the exact same subject. The
default value is yes, to be compatible with older (pre 0.9.8) versions of OpenSSL. However, to make
CA certificate roll-over easier, it's recommended to use the value no, especially if combined with
the -selfsign command line option.
Note that it is valid in some circumstances for certificates to be created without any subject. In
the case where there are multiple certificates without subjects this does not count as a duplicate.
serial
A text file containing the next serial number to use in hex. Mandatory. This file must be present
and contain a valid serial number.
crlnumber
A text file containing the next CRL number to use in hex. The crl number will be inserted in the CRLs
only if this file exists. If this file is present, it must contain a valid CRL number.
x509_extensions
The same as -extensions.
crl_extensions
The same as -crlexts.
preserve
The same as -preserveDN
email_in_dn
The same as -noemailDN. If you want the EMAIL field to be removed from the DN of the certificate
simply set this to 'no'. If not present the default is to allow for the EMAIL filed in the
certificate's DN.
msie_hack
The same as -msie_hack
policy
The same as -policy. Mandatory. See the POLICY FORMAT section for more information.
name_opt, cert_opt
These options allow the format used to display the certificate details when asking the user to
confirm signing. All the options supported by the x509 utilities -nameopt and -certopt switches can
be used here, except the no_signame and no_sigdump are permanently set and cannot be disabled (this
is because the certificate signature cannot be displayed because the certificate has not been signed
at this point).
For convenience the values ca_default are accepted by both to produce a reasonable output.
If neither option is present the format used in earlier versions of OpenSSL is used. Use of the old
format is strongly discouraged because it only displays fields mentioned in the policy section,
mishandles multicharacter string types and does not display extensions.
copy_extensions
Determines how extensions in certificate requests should be handled. If set to none or this option
is not present then extensions are ignored and not copied to the certificate. If set to copy then any
extensions present in the request that are not already present are copied to the certificate. If set
to copyall then all extensions in the request are copied to the certificate: if the extension is
already present in the certificate it is deleted first. See the WARNINGS section before using this
option.
The main use of this option is to allow a certificate request to supply values for certain extensions
such as subjectAltName.
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 '.'.
When processing SPKAC format, the output is DER if the -out flag is used, but PEM format if sending to
stdout or the -outdir flag is used.
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
#rand_serial = yes # for random serial#'s
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
email_in_dn = no # Don't add the email into cert DN
name_opt = ca_default # Subject name display option
cert_opt = ca_default # Certificate display option
copy_extensions = none # Don't copy extensions from request
[ policy_any ]
countryName = supplied
stateOrProvinceName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
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
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.
V2 CRL features like delta CRLs 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.
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 script
CA.pl helps 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. To enforce the absence of the EMAIL field within the DN, as suggested by
RFCs, regardless the contents of the request' subject the -noemailDN option can be used. The behaviour
should be more friendly and configurable.
Canceling some commands by refusing to certify a certificate can create an empty file.
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 to 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.
The copy_extensions option should be used with caution. If care is not taken then it can be a security
risk. For example if a certificate request contains a basicConstraints extension with CA:TRUE and the
copy_extensions value is set to copyall and the user does not spot this when the certificate is displayed
then this will hand the requester a valid CA certificate.
This situation can be avoided by setting copy_extensions to copy and including basicConstraints with
CA:FALSE in the configuration file. Then if the request contains a basicConstraints extension it will be
ignored.
It is advisable to also include values for other extensions such as keyUsage to prevent a request
supplying its own values.
Additional restrictions can be placed on the CA certificate itself. For example if the CA certificate
has:
basicConstraints = CA:TRUE, pathlen:0
then even if a certificate is issued with CA:TRUE it will not be valid.
HISTORY
Since OpenSSL 1.1.1, the program follows RFC5280. Specifically, certificate validity period (specified by
any of -startdate, -enddate and -days) will be encoded as UTCTime if the dates are earlier than year 2049
(included), and as GeneralizedTime if the dates are in year 2050 or later.
SEE ALSO
req(1), spkac(1), x509(1), CA.pl(1), config(5), x509v3_config(5)
COPYRIGHT
Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with
the License. You can obtain a copy in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.
1.1.1f 2025-02-05 CA(1SSL)