/usr/man/cat.1/openssl-req.1
REQ(1) OpenSSL REQ(1)
NAME
openssl-req, req - PKCS#10 certificate request and
certificate generating utility.
SYNOPSIS
openssl req [-inform PEM|DER] [-outform PEM|DER] [-in
filename] [-passin arg] [-out filename] [-passout arg]
[-text] [-pubkey] [-noout] [-verify] [-modulus] [-new]
[-rand file(s)] [-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]
[-asn1-kludge] [-no-asn1-kludge] [-newhdr] [-extensions
section] [-reqexts section] [-utf8] [-nameopt] [-reqopt]
[-subject] [-subj arg] [-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.
COMMAND OPTIONS
-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 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.
-passin arg
the input file password source. For more information
about the format of arg see the PASS PHRASE ARGUMENTS
section 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 the PASS PHRASE ARGUMENTS
section in openssl(1).
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-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.
-subj arg
Replaces subject field of input request with specified
data and outputs modified request. The arg must be
formatted as /type0=value0/type1=value1/type2=...,
characters may be escaped by \ (backslash), no spaces
are skipped.
-rand file(s)
a file or files containing random data used to seed the
random number generator, or an EGD socket (see
RAND_egd(3)). Multiple files can be specified separated
by a OS-dependent character. The separator is ; for
MS-Windows, , for OpenVMS, and : for all others.
-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
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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 approriate 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 neccessary 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
with (such as -md5, -sha1). This overrides the digest
algorithm specified in the configuration file.
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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).
-config filename
this allows an alternative configuration file to be
specified, this overrides the compile time filename or
any specified in the OPENSSL_CONF environment variable.
-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=...,
characters may be escaped by \ (backslash), no spaces
are skipped.
-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. 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. It is possible to use
negative serial numbers but this is not recommended.
-extensions section
-reqexts section
these options specify alternative sections to include
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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.
-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 discission of the -certopt parameter in the x509
command.
-asn1-kludge
by default the req command outputs certificate requests
containing no attributes in the correct PKCS#10 format.
However certain CAs will only accept requests containing
no attributes in an invalid form: this option produces
this invalid format.
More precisely the Attributes in a PKCS#10 certificate
request are defined as a SET OF Attribute. They are not
OPTIONAL so if no attributes are present then they
should be encoded as an empty SET OF. The invalid form
does not include the empty SET OF whereas the correct
form does.
It should be noted that very few CAs still require the
use of this option.
-no-asn1-kludge
Reverses effect of -asn1-kludge
-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.
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-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.
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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
This specifies a filename in which random number seed
information is placed and read from, or an EGD socket
(see RAND_egd(3)). 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.
Possible values include md5 sha1 mdc2. This option can
be overridden on the command line.
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
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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@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
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"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 include 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:
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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
x509_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 = CA:true
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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@email.address
[ req_attributes ]
challengePassword = A challenge password
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
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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.
ENVIRONMENT VARIABLES
The variable OPENSSL_CONF if defined allows an alternative
configuration file location to be specified, it will be
overridden by the -config command line switch if it is
present. For compatibility reasons the SSLEAY_CONF
environment variable serves the same purpose but its use is
discouraged.
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
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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)
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See also req(1)
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