OPENSSL-CA(1SSL) OpenSSL OPENSSL-CA(1SSL)
NAME
openssl-ca - sample minimal CA application
SYNOPSIS
openssl ca [-help] [-verbose] [-config filename] [-name section]
[-section section] [-gencrl] [-revoke file] [-valid file] [-status
serial] [-updatedb] [-crl_reason reason] [-crl_hold instruction]
[-crl_compromise time] [-crl_CA_compromise time] [-crl_lastupdate date]
[-crl_nextupdate date] [-crldays days] [-crlhours hours] [-crlsec
seconds] [-crlexts section] [-startdate date] [-enddate date] [-days
arg] [-md arg] [-policy arg] [-keyfile filename|uri] [-keyform
DER|PEM|P12|ENGINE] [-key arg] [-passin arg] [-cert file] [-certform
DER|PEM|P12] [-selfsign] [-in file] [-inform DER|<PEM>] [-out file]
[-notext] [-dateopt] [-outdir dir] [-infiles] [-spkac file] [-ss_cert
file] [-preserveDN] [-noemailDN] [-batch] [-msie_hack] [-extensions
section] [-extfile section] [-subj arg] [-utf8] [-sigopt nm:v] [-vfyopt
nm:v] [-create_serial] [-rand_serial] [-multivalue-rdn] [-rand files]
[-writerand file] [-engine id] [-provider name] [-provider-path path]
[-propquery propq] [certreq...]
DESCRIPTION
This command emulates a CA application. See the WARNINGS especially
when considering to use it productively. It can be used to sign
certificate requests (CSRs) in a variety of forms and generate
certificate revocation lists (CRLs). It also maintains a text database
of issued certificates and their status. When signing certificates, a
single request can be specified with the -in option, or multiple
requests can be processed by specifying a set of certreq files after
all options.
Note that there are also very lean ways of generating certificates: the
req and x509 commands can be used for directly creating certificates.
See openssl-req(1) and openssl-x509(1) for details.
The descriptions of the ca command options are 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, -section 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 (CSR) to
be signed by the CA.
-inform DER|PEM
The format of the data in certificate request input files;
unspecified by default. See openssl-format-options(1) for details.
-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 filename
The CA certificate, which must match with -keyfile.
-certform DER|PEM|P12
The format of the data in certificate input files; unspecified by
default. See openssl-format-options(1) for details.
-keyfile filename|uri
The CA private key to sign certificate requests with. This must
match with -cert.
-keyform DER|PEM|P12|ENGINE
The format of the private key input file; unspecified by default.
See openssl-format-options(1) for details.
-sigopt nm:v
Pass options to the signature algorithm during sign operations.
Names and values of these options are algorithm-specific.
-vfyopt nm:v
Pass options to the signature algorithm during verify operations.
Names and values of these options are algorithm-specific.
This often needs to be given while signing too, because the self-
signature of a certificate signing request (CSR) is verified
against the included public key, and that verification may need its
own set of options.
-key password
The password used to encrypt the private key. Since on some systems
the command line arguments are visible (e.g., when using ps(1) on
Unix), this option should be used with caution. Better use
-passin.
-passin arg
The key password source for key files and certificate PKCS#12
files. For more information about the format of arg see
openssl-passphrase-options(1).
-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.
-notext
Don't output the text form of a certificate to the output file.
-dateopt
Specify the date output format. Values are: rfc_822 and iso_8601.
Defaults to rfc_822.
-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(1) 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 this command 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 X.509
extensions are specified then a V1 certificate is created, else 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).
-subj arg
Supersedes subject name given in the request.
The arg must be formatted as
"/type0=value0/type1=value1/type2=...". Special characters may be
escaped by "\" (backslash), whitespace is retained. Empty values
are permitted, but the corresponding type will not be included in
the resulting certificate. Giving a single "/" will lead to an
empty sequence of RDNs (a NULL-DN). Multi-valued RDNs can be
formed by placing a "+" character instead of a "/" between the
AttributeValueAssertions (AVAs) that specify the members of the
set. Example:
"/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe"
-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 has been deprecated and has no effect.
-rand files, -writerand file
See "Random State Options" in openssl(1) for details.
-engine id
See "Engine Options" in openssl(1). This option is deprecated.
-provider name
-provider-path path
-propquery propq
See "Provider Options" in openssl(1), provider(7), and property(7).
CRL OPTIONS
-gencrl
This option generates a CRL based on information in the index file.
-crl_lastupdate time
Allows the value of the CRL's lastUpdate field to be explicitly
set; if this option is not present, the current time is used.
Accepts times in YYMMDDHHMMSSZ format (the same as an ASN1 UTCTime
structure) or YYYYMMDDHHMMSSZ format (the same as an ASN1
GeneralizedTime structure).
-crl_nextupdate time
Allows the value of the CRL's nextUpdate field to be explicitly
set; if this option is present, any values given for -crldays,
-crlhours and -crlsec are ignored. Accepts times in the same
formats as -crl_lastupdate.
-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.
-crlsec num
The number of seconds 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 this
command 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 whitespace then the short name
followed by whitespace 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. (Note:
Using a RANDFILE is not necessary anymore, see the "HISTORY"
section.
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
A fallback to the -extensions option.
crl_extensions
A fallback to the -crlexts option.
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 openssl-spkac(1).
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 directory structure this command
assumes is already set up and the relevant files already exist. This
usually involves creating a CA certificate and private key with
openssl-req(1), 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 an SM2 certificate request:
openssl ca -in sm2.csr -out sm2.crt -md sm3 \
-sigopt "distid:1234567812345678" \
-vfyopt "distid:1234567812345678"
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 this
command:
[ 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
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
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
This command is quirky and at times downright unfriendly.
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.
This command really needs rewriting or the required functionality
exposed at either a command or interface level so that a more user-
friendly replacement could 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
This command was originally meant as an example of how to do things in
a CA. Its code does not have production quality. It was not supposed
to be used as a full blown CA itself, nevertheless some people are
using it for this purpose at least internally. When doing so, specific
care should be taken to properly secure the private key(s) used for
signing certificates. It is advisable to keep them in a secure HW
storage such as a smart card or HSM and access them via a suitable
engine or crypto provider.
This command command is effectively a single user command: no locking
is done on the various files and attempts to run more than one openssl
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) and CRL last/next update time (specified by any of
-crl_lastupdate, -crl_nextupdate, -crldays, -crlhours and -crlsec) 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.
OpenSSL 1.1.1 introduced a new random generator (CSPRNG) with an
improved seeding mechanism. The new seeding mechanism makes it
unnecessary to define a RANDFILE for saving and restoring randomness.
This option is retained mainly for compatibility reasons.
The -section option was added in OpenSSL 3.0.0.
The -multivalue-rdn option has become obsolete in OpenSSL 3.0.0 and has
no effect.
The -engine option was deprecated in OpenSSL 3.0.
SEE ALSO
openssl(1), openssl-req(1), openssl-spkac(1), openssl-x509(1),
CA.pl(1), config(5), x509v3_config(5)
COPYRIGHT
Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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>.
3.0.13 2025-09-18 OPENSSL-CA(1SSL)
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