REQ(1) OpenSSL REQ(1)
NAME
openssl-req, req - PKCS#10 certificate request and certificate
generating utility
SYNOPSIS
openssl req [-help] [-inform PEM|DER] [-outform PEM|DER] [-in filename]
[-passin arg] [-out filename] [-passout arg] [-text] [-pubkey] [-noout]
[-verify] [-modulus] [-new] [-rand file...] [-writerand file] [-newkey
rsa:bits] [-newkey alg:file] [-nodes] [-key filename] [-keyform
PEM|DER] [-keyout filename] [-keygen_engine id] [-digest] [-config
filename] [-multivalue-rdn] [-x509] [-days n] [-set_serial n] [-newhdr]
[-addext ext] [-extensions section] [-reqexts section] [-precert]
[-utf8] [-nameopt] [-reqopt] [-subject] [-subj arg] [-sigopt nm:v]
[-batch] [-verbose] [-engine id]
DESCRIPTION
The req command primarily creates and processes certificate requests in
PKCS#10 format. It can additionally create self signed certificates for
use as root CAs for example.
OPTIONS
-help
Print out a usage message.
-inform DER|PEM
This specifies the input format. The DER option uses an ASN1 DER
encoded form compatible with the PKCS#10. The PEM form is the
default format: it consists of the DER format base64 encoded with
additional header and footer lines.
-outform DER|PEM
This specifies the output format, the options have the same meaning
and default as the -inform option.
-in filename
This specifies the input filename to read a request from or
standard input if this option is not specified. A request is only
read if the creation options (-new and -newkey) are not specified.
-sigopt nm:v
Pass options to the signature algorithm during sign or verify
operations. Names and values of these options are algorithm-
specific.
-passin arg
The input file password source. For more information about the
format of arg see "Pass Phrase Options" in openssl(1).
-out filename
This specifies the output filename to write to or standard output
by default.
-passout arg
The output file password source. For more information about the
format of arg see "Pass Phrase Options" in openssl(1).
-text
Prints out the certificate request in text form.
-subject
Prints out the request subject (or certificate subject if -x509 is
specified)
-pubkey
Outputs the public key.
-noout
This option prevents output of the encoded version of the request.
-modulus
This option prints out the value of the modulus of the public key
contained in the request.
-verify
Verifies the signature on the request.
-new
This option generates a new certificate request. It will prompt the
user for the relevant field values. The actual fields prompted for
and their maximum and minimum sizes are specified in the
configuration file and any requested extensions.
If the -key option is not used it will generate a new RSA private
key using information specified in the configuration file.
-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.
-newkey arg
This option creates a new certificate request and a new private
key. The argument takes one of several forms. rsa:nbits, where
nbits is the number of bits, generates an RSA key nbits in size. If
nbits is omitted, i.e. -newkey rsa specified, the default key size,
specified in the configuration file is used.
All other algorithms support the -newkey alg:file form, where file
may be an algorithm parameter file, created by the genpkey
-genparam command or and X.509 certificate for a key with
appropriate algorithm.
param:file generates a key using the parameter file or certificate
file, the algorithm is determined by the parameters. algname:file
use algorithm algname and parameter file file: the two algorithms
must match or an error occurs. algname just uses algorithm algname,
and parameters, if necessary should be specified via -pkeyopt
parameter.
dsa:filename generates a DSA key using the parameters in the file
filename. ec:filename generates EC key (usable both with ECDSA or
ECDH algorithms), gost2001:filename generates GOST R 34.10-2001 key
(requires ccgost engine configured in the configuration file). If
just gost2001 is specified a parameter set should be specified by
-pkeyopt paramset:X
-pkeyopt opt:value
Set the public key algorithm option opt to value. The precise set
of options supported depends on the public key algorithm used and
its implementation. See KEY GENERATION OPTIONS in the genpkey
manual page for more details.
-key filename
This specifies the file to read the private key from. It also
accepts PKCS#8 format private keys for PEM format files.
-keyform PEM|DER
The format of the private key file specified in the -key argument.
PEM is the default.
-keyout filename
This gives the filename to write the newly created private key to.
If this option is not specified then the filename present in the
configuration file is used.
-nodes
If this option is specified then if a private key is created it
will not be encrypted.
-digest
This specifies the message digest to sign the request. Any digest
supported by the OpenSSL dgst command can be used. This overrides
the digest algorithm specified in the configuration file.
Some public key algorithms may override this choice. For instance,
DSA signatures always use SHA1, GOST R 34.10 signatures always use
GOST R 34.11-94 (-md_gost94), Ed25519 and Ed448 never use any
digest.
-config filename
This allows an alternative configuration file to be specified.
Optional; for a description of the default value, see "COMMAND
SUMMARY" in openssl(1).
-subj arg
Sets subject name for new request or supersedes the subject name
when processing a 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 request.
-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.
-x509
This option outputs a self signed certificate instead of a
certificate request. This is typically used to generate a test
certificate or a self signed root CA. The extensions added to the
certificate (if any) are specified in the configuration file.
Unless specified using the set_serial option, a large random number
will be used for the serial number.
If existing request is specified with the -in option, it is
converted to the self signed certificate otherwise new request is
created.
-days n
When the -x509 option is being used this specifies the number of
days to certify the certificate for, otherwise it is ignored. n
should be a positive integer. The default is 30 days.
-set_serial n
Serial number to use when outputting a self signed certificate.
This may be specified as a decimal value or a hex value if preceded
by 0x.
-addext ext
Add a specific extension to the certificate (if the -x509 option is
present) or certificate request. The argument must have the form
of a key=value pair as it would appear in a config file.
This option can be given multiple times.
-extensions section
-reqexts section
These options specify alternative sections to include certificate
extensions (if the -x509 option is present) or certificate request
extensions. This allows several different sections to be used in
the same configuration file to specify requests for a variety of
purposes.
-precert
A poison extension will be added to the certificate, making it a
"pre-certificate" (see RFC6962). This can be submitted to
Certificate Transparency logs in order to obtain signed certificate
timestamps (SCTs). These SCTs can then be embedded into the pre-
certificate as an extension, before removing the poison and signing
the certificate.
This implies the -new flag.
-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.
-nameopt option
Option which determines how the subject or issuer names are
displayed. The option argument can be a single option or multiple
options separated by commas. Alternatively the -nameopt switch may
be used more than once to set multiple options. See the x509(1)
manual page for details.
-reqopt
Customise the output format used with -text. The option argument
can be a single option or multiple options separated by commas.
See discussion of the -certopt parameter in the x509(1) command.
-newhdr
Adds the word NEW to the PEM file header and footer lines on the
outputted request. Some software (Netscape certificate server) and
some CAs need this.
-batch
Non-interactive mode.
-verbose
Print extra details about the operations being performed.
-engine id
Specifying an engine (by its unique id string) will cause req 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.
-keygen_engine id
Specifies an engine (by its unique id string) which would be used
for key generation operations.
CONFIGURATION FILE FORMAT
The configuration options are specified in the req section of the
configuration file. As with all configuration files if no value is
specified in the specific section (i.e. req) then the initial unnamed
or default section is searched too.
The options available are described in detail below.
input_password output_password
The passwords for the input private key file (if present) and the
output private key file (if one will be created). The command line
options passin and passout override the configuration file values.
default_bits
Specifies the default key size in bits.
This option is used in conjunction with the -new option to generate
a new key. It can be overridden by specifying an explicit key size
in the -newkey option. The smallest accepted key size is 512 bits.
If no key size is specified then 2048 bits is used.
default_keyfile
This is the default filename to write a private key to. If not
specified the key is written to standard output. This can be
overridden by the -keyout option.
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.
RANDFILE
At startup the specified file is loaded into the random number
generator, and at exit 256 bytes will be written to it. It is used
for private key generation.
encrypt_key
If this is set to no then if a private key is generated it is not
encrypted. This is equivalent to the -nodes command line option.
For compatibility encrypt_rsa_key is an equivalent option.
default_md
This option specifies the digest algorithm to use. Any digest
supported by the OpenSSL dgst command can be used. This option can
be overridden on the command line. Certain signing algorithms (i.e.
Ed25519 and Ed448) will ignore any digest that has been set.
string_mask
This option masks out the use of certain string types in certain
fields. Most users will not need to change this option.
It can be set to several values default which is also the default
option uses PrintableStrings, T61Strings and BMPStrings if the pkix
value is used then only PrintableStrings and BMPStrings will be
used. This follows the PKIX recommendation in RFC2459. If the
utf8only option is used then only UTF8Strings will be used: this is
the PKIX recommendation in RFC2459 after 2003. Finally the nombstr
option just uses PrintableStrings and T61Strings: certain software
has problems with BMPStrings and UTF8Strings: in particular
Netscape.
req_extensions
This specifies the configuration file section containing a list of
extensions to add to the certificate request. It can be overridden
by the -reqexts command line switch. See the x509v3_config(5)
manual page for details of the extension section format.
x509_extensions
This specifies the configuration file section containing a list of
extensions to add to certificate generated when the -x509 switch is
used. It can be overridden by the -extensions command line switch.
prompt
If set to the value no this disables prompting of certificate
fields and just takes values from the config file directly. It also
changes the expected format of the distinguished_name and
attributes sections.
utf8
If set to the value yes then 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.
attributes
This specifies the section containing any request attributes: its
format is the same as distinguished_name. Typically these may
contain the challengePassword or unstructuredName types. They are
currently ignored by OpenSSL's request signing utilities but some
CAs might want them.
distinguished_name
This specifies the section containing the distinguished name fields
to prompt for when generating a certificate or certificate request.
The format is described in the next section.
DISTINGUISHED NAME AND ATTRIBUTE SECTION FORMAT
There are two separate formats for the distinguished name and attribute
sections. If the prompt option is set to no then these sections just
consist of field names and values: for example,
CN=My Name
OU=My Organization
emailAddress=someone AT somewhere.org
This allows external programs (e.g. GUI based) to generate a template
file with all the field names and values and just pass it to req. An
example of this kind of configuration file is contained in the EXAMPLES
section.
Alternatively if the prompt option is absent or not set to no then the
file contains field prompting information. It consists of lines of the
form:
fieldName="prompt"
fieldName_default="default field value"
fieldName_min= 2
fieldName_max= 4
"fieldName" is the field name being used, for example commonName (or
CN). The "prompt" string is used to ask the user to enter the relevant
details. If the user enters nothing then the default value is used if
no default value is present then the field is omitted. A field can
still be omitted if a default value is present if the user just enters
the '.' character.
The number of characters entered must be between the fieldName_min and
fieldName_max limits: there may be additional restrictions based on the
field being used (for example countryName can only ever be two
characters long and must fit in a PrintableString).
Some fields (such as organizationName) can be used more than once in a
DN. This presents a problem because configuration files will not
recognize the same name occurring twice. To avoid this problem if the
fieldName contains some characters followed by a full stop they will be
ignored. So for example a second organizationName can be input by
calling it "1.organizationName".
The actual permitted field names are any object identifier short or
long names. These are compiled into OpenSSL and include the usual
values such as commonName, countryName, localityName, organizationName,
organizationalUnitName, stateOrProvinceName. Additionally emailAddress
is included as well as name, surname, givenName, initials, and
dnQualifier.
Additional object identifiers can be defined with the oid_file or
oid_section options in the configuration file. Any additional fields
will be treated as though they were a DirectoryString.
EXAMPLES
Examine and verify certificate request:
openssl req -in req.pem -text -verify -noout
Create a private key and then generate a certificate request from it:
openssl genrsa -out key.pem 2048
openssl req -new -key key.pem -out req.pem
The same but just using req:
openssl req -newkey rsa:2048 -keyout key.pem -out req.pem
Generate a self signed root certificate:
openssl req -x509 -newkey rsa:2048 -keyout key.pem -out req.pem
Example of a file pointed to by the oid_file option:
1.2.3.4 shortName A longer Name
1.2.3.6 otherName Other longer Name
Example of a section pointed to by oid_section making use of variable
expansion:
testoid1=1.2.3.5
testoid2=${testoid1}.6
Sample configuration file prompting for field values:
[ req ]
default_bits = 2048
default_keyfile = privkey.pem
distinguished_name = req_distinguished_name
attributes = req_attributes
req_extensions = v3_ca
dirstring_type = nobmp
[ req_distinguished_name ]
countryName = Country Name (2 letter code)
countryName_default = AU
countryName_min = 2
countryName_max = 2
localityName = Locality Name (eg, city)
organizationalUnitName = Organizational Unit Name (eg, section)
commonName = Common Name (eg, YOUR name)
commonName_max = 64
emailAddress = Email Address
emailAddress_max = 40
[ req_attributes ]
challengePassword = A challenge password
challengePassword_min = 4
challengePassword_max = 20
[ v3_ca ]
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid:always,issuer:always
basicConstraints = critical, CA:true
Sample configuration containing all field values:
RANDFILE = $ENV::HOME/.rnd
[ req ]
default_bits = 2048
default_keyfile = keyfile.pem
distinguished_name = req_distinguished_name
attributes = req_attributes
prompt = no
output_password = mypass
[ req_distinguished_name ]
C = GB
ST = Test State or Province
L = Test Locality
O = Organization Name
OU = Organizational Unit Name
CN = Common Name
emailAddress = test AT email.address
[ req_attributes ]
challengePassword = A challenge password
Example of giving the most common attributes (subject and extensions)
on the command line:
openssl req -new -subj "/C=GB/CN=foo" \
-addext "subjectAltName = DNS:foo.co.uk" \
-addext "certificatePolicies = 1.2.3.4" \
-newkey rsa:2048 -keyout key.pem -out req.pem
NOTES
The header and footer lines in the PEM format are normally:
-----BEGIN CERTIFICATE REQUEST-----
-----END CERTIFICATE REQUEST-----
some software (some versions of Netscape certificate server) instead
needs:
-----BEGIN NEW CERTIFICATE REQUEST-----
-----END NEW CERTIFICATE REQUEST-----
which is produced with the -newhdr option but is otherwise compatible.
Either form is accepted transparently on input.
The certificate requests generated by Xenroll with MSIE have extensions
added. It includes the keyUsage extension which determines the type of
key (signature only or general purpose) and any additional OIDs entered
by the script in an extendedKeyUsage extension.
DIAGNOSTICS
The following messages are frequently asked about:
Using configuration from /some/path/openssl.cnf
Unable to load config info
This is followed some time later by...
unable to find 'distinguished_name' in config
problems making Certificate Request
The first error message is the clue: it can't find the configuration
file! Certain operations (like examining a certificate request) don't
need a configuration file so its use isn't enforced. Generation of
certificates or requests however does need a configuration file. This
could be regarded as a bug.
Another puzzling message is this:
Attributes:
a0:00
this is displayed when no attributes are present and the request
includes the correct empty SET OF structure (the DER encoding of which
is 0xa0 0x00). If you just see:
Attributes:
then the SET OF is missing and the encoding is technically invalid (but
it is tolerated). See the description of the command line option
-asn1-kludge for more information.
BUGS
OpenSSL's handling of T61Strings (aka TeletexStrings) is broken: it
effectively treats them as ISO-8859-1 (Latin 1), Netscape and MSIE have
similar behaviour. This can cause problems if you need characters that
aren't available in PrintableStrings and you don't want to or can't use
BMPStrings.
As a consequence of the T61String handling the only correct way to
represent accented characters in OpenSSL is to use a BMPString:
unfortunately Netscape currently chokes on these. If you have to use
accented characters with Netscape and MSIE then you currently need to
use the invalid T61String form.
The current prompting is not very friendly. It doesn't allow you to
confirm what you've just entered. Other things like extensions in
certificate requests are statically defined in the configuration file.
Some of these: like an email address in subjectAltName should be input
by the user.
SEE ALSO
x509(1), ca(1), genrsa(1), gendsa(1), config(5), x509v3_config(5)
COPYRIGHT
Copyright 2000-2021 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>;.
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