NAME
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 dsa:file] [-nodes] [-key filename] [-keyform PEM|DER] [-keyout filename] [-[md5|sha1|md2|mdc2]] [-config filename] [-subj arg] [-x509] [-days n] [-set_serial n] [-asn1-kludge] [-newhdr] [-extensions section] [-reqexts section] [-utf8] [-nameopt] [-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 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).
-text
prints out the certificate request in text form.
-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(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 two forms. rsa:nbits, where nbits
is the number of bits, generates an RSA key nbits in size. dsa:filename
generates a DSA key using the parameters in the file filename.
-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.
-[md5|sha1|md2|mdc2]
this specifies the message digest to sign the request with.
This overrides the digest algorithm specified in the configuration
file. This option is ignored for DSA requests: they always use SHA1.
-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.
-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 0 will be used for the serial number.
-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.
-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.
-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.
-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.
-newhdr
Adds the word NEW to the PEM file header and footer lines
on the outputed 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 it's 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.
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
This specifies the default key size in bits. If not specified
then 512 is used. It is used if the -new option is used. It can
be overridden by using the -newkey option.
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
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. If not present then MD5 is used. 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.
Ø
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.
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@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,
organizationUnitName, 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 1024
openssl req -new -key key.pem -out req.pem |
The same but just using req:
openssl req -newkey rsa:1024 -keyout key.pem -out req.pem |
Generate a self signed root certificate:
openssl req -x509 -newkey rsa:1024 -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 | ø
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 = 1024
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 |
Sample configuration containing all field values:
RANDFILE = $ENV::HOME/.rnd
[ req ]
default_bits = 1024
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 |
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:
<
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:
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.
Restrictions
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)
