req(1ssl)req(1ssl)NAMEreq - PKCS#10 certificate and certificate generating utility
SYNOPSIS
openssl req [-inform PEM | DER] [-outform PEM | DER] [-in filename]
[-passin arg] [-out filename] [-passoutarg] [-text] [-noout] [-verify]
[-modulus] [-new] [-randfilename] [-newkeyrsa:bits] [-newkey dsa:file]
[-nodes] [-key filename] [-keyform PEM | DER] [-keyoutfilename] [--md5
| sha1 | md2 | mdc2] [-configfilename] [-x509] [-daysn] [-asn1-kludge]
[-newhdr] [-extensionssection] [-reqextssection]
OPTIONS
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. Specifies the output format. The options have the same
meaning as the -inform option. 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. Input file password source. For more information about the
format of arg, see the Pass Phrase Arguments section in openssl(1).
Specifies the output filename to write to or standard output by
default. Output file password source. For more information about the
format of arg, see the Pass Phrase Arguments section in openssl(1).
Prints out the certificate request in text form. Prevents output of
the encoded version of the request. Prints out the value of the modu‐
lus of the public key contained in the request. Verifies the signature
on the request. 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 pri‐
vate key using information specified in the configuration file.
A file or files containing random data used to seed the random
number generator, or an EGD socket. (See RAND_egd(3).) Multiple
files are separated by an OS-dependent character. The separator
is a semicolon (;) for MS-Windows, a comma (,) for OpenVMS, and
a colon (:) for all others. Creates a new certificate request
and a new private key. The argument takes one of two forms. The
rsa:nbits, where nbits is the number of bits, generates an RSA
key nbits in size. The dsa:filename generates a DSA key using
the parameters in the file filename. Specifies the file to read
the private key from. It also accepts PKCS#8 format private keys
for PEM format files. The format of the private key file speci‐
fied in the -key option. The PEM format is the default. Gives
the filename to write the newly created private key to. If this
option is not specified then the filename present in the config‐
uration file is used. If this option is specified then if a
private key is created it will not be encrypted. 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.
Allows an alternative configuration file to be specified. This
overrides the compile time filename or any specified in the
OPENSSL_CONF environment variable. Outputs a self-signed cer‐
tificate 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. When the -x509 option is being used
this specifies the number of days to certify the certificate.
The default is 30 days. Specifies alternative sections to
include certificate extensions (if the -x509 option is present)
or certificate request extensions. This allows several differ‐
ent sections to be used in the same configuration file to spec‐
ify requests for a variety of purposes. By default the req com‐
mand 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. 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.
CONFIGURATION OPTIONS
The configuration options are specified in the req section of the con‐
figuration file. As with all configuration files if no value is speci‐
fied 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. 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. 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. 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. 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. 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. 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. 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. Specifies the digest algo‐
rithm to use. Possible values include md5 sha1 mdc2. If not present
then MD5 is used. This option can be overridden on the command line.
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. The default option uses Printa‐
bleStrings, 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 uses PrintableStrings and T61Strings. Certain software
has problems with BMPStrings and UTF8Strings, particularly Net‐
scape. 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 option. Specifies the
configuration file section containing a list of extensions to
add to the certificate generated when the -x509 option is used.
It can be overridden by the -extensions command line option. If
set to the value no this disables prompting of certificate
fields and takes values from the config file directly. It also
changes the expected format of the distinguished_name and
attributes sections. Specifies the section containing any
request attributes. Its format is the same as distin‐
guished_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. Specifies the section containing the distinguished name
fields to prompt for when generating a certificate or certifi‐
cate request. The format is described in the next section.
DISTINGUISHED NAME AND ATTRIBUTES SECTIONS FORMAT
There are two separate formats for the distinguished name and attribute
sections. If the prompt option is set to no then these sections only
consist of field names and values. An example follows:
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 pass it to req. An exam‐
ple 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 such
as the following:
fieldName="prompt"
fieldName_default="default field value"
fieldName_min= 2
fieldName_max= 4
The fieldName is the field name being used, such as 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 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 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 recog‐
nize the same name occurring twice. To avoid this problem if the field‐
Name 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 val‐
ues such as commonName, countryName, localityName, organizationName,
organizationUnitName, stateOrPrivinceName. 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.
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.
NOTES
The header and footer lines in the PEM format are normally:
-----BEGIN CERTIFICATE REQUEST----
-----END CERTIFICATE REQUEST----
Some software, including some versions of Netscape certificate server,
need:
-----BEGIN NEW CERTIFICATE REQUEST----
-----END NEW CERTIFICATE REQUEST----
This 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.
RESTRICTIONS
OpenSSL's handling of T61Strings (also known as TeletexStrings) is bro‐
ken. It effectively treats them as ISO-8859-1 (Latin 1). Netscape and
MSIE have similar behavior. This can cause problems if you need charac‐
ters that are not available in PrintableStrings and you do not want to
or cannot use BMPStrings.
As a consequence of the T61String handling the only correct way to rep‐
resent accented characters in OpenSSL is to use a BMPString. Unfortu‐
nately 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 entered. Other things, such as extensions in cer‐
tificate requests, are statically defined in the configuration file.
Some of these, such as an email address in subjectAltName, should be
input by the user.
ERRORS
The following messages are frequently asked about: Using configu‐
ration from /some/path/openssl.cnf Unable to load config info
This is followed some time later by the following lines: unable to
find 'distinguished_name' in config problems making Certificate
Request
The first error message is the clue. It means the configuration file
cannot be found. Certain operations, such as examining a certificate
request, do not need a configuration file; so its use isn't enforced.
Generation of certificates or requests, however, do need a configura‐
tion file.
Another error 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 only 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.
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 short‐
Name 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 = 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
ENVIRONMENT VARIABLES
If defined, the variable OPENSSL_CONF allows an alternative configura‐
tion file location to be specified. It will be overridden by the -con‐
fig command line option if it is present. For compatibility reasons the
SSLEAY_CONF environment variable serves the same purpose, but its use
is discouraged.
SEE ALSO
Commands: x509(1ssl), ca(1ssl), genrsa(1ssl), gendsa(1ssl)
Others: config(5)req(1ssl)
