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 alg:file] [
-nodes] [
-key
filename] [
-keyform PEM|DER] [
-keyout filename] [
-keygen_engine id] [
-[digest]] [
-config filename] [
-subj arg] [
-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).
- -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 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.
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 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.
- -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.
- -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.
- -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.
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.
- 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.
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,
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 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
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:
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 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)