=pod

=head1 NAME

req - PKCS#10 certificate and certificate generating utility.

=head1 SYNOPSIS

B<openssl> B<req>
[B<-inform PEM|DER>]
[B<-outform PEM|DER>]
[B<-in filename>]
[B<-out filename>]
[B<-text>]
[B<-noout>]
[B<-verify>]
[B<-modulus>]
[B<-new>]
[B<-newkey rsa:bits>]
[B<-newkey dsa:file>]
[B<-nodes>]
[B<-key filename>]
[B<-keyform PEM|DER>]
[B<-keyout filename>]
[B<-[md5|sha1|md2|mdc2]>]
[B<-config filename>]
[B<-x509>]
[B<-days n>]
[B<-noasn1-kludge>]
[B<-extensions section>]
[B<-reqexts section>]

=head1 DESCRIPTION

The B<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.

=head1 COMMAND OPTIONS

=over 4

=item B<-inform DER|PEM>

This specifies the input format. The B<DER> option uses an ASN1 DER encoded
form compatible with the PKCS#10. The B<PEM> form is the default format: it
consists of the B<DER> format base64 encoded with additional header and
footer lines.

=item B<-outform DER|PEM>

This specifies the output format, the options have the same meaning as the 
B<-inform> option.

=item B<-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 (B<-new> and B<-newkey>) are not specified.

=item B<-out filename>

This specifies the output filename to write to or standard output by
default.

=item B<-text>

prints out the certificate request in text form.

=item B<-noout>

this option prevents output of the encoded version of the request.

=item B<-modulus>

this option prints out the value of the modulus of the public key
contained in the request.

=item B<-verify>

verifies the signature on the request.

=item B<-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 B<-key> option is not used it will generate a new RSA private
key using information specified in the configuration file.

=item B<-newkey arg>

this option creates a new certificate request and a new private
key. The argument takes one of two forms. B<rsa:nbits>, where
B<nbits> is the number of bits, generates an RSA key B<nbits>
in size. B<dsa:filename> generates a DSA key using the parameters
in the file B<filename>.

=item B<-key filename>

This specifies the file to read the private key from. It also
accepts PKCS#8 format private keys for PEM format files.

=item B<-keyform PEM|DER>

the format of the private key file specified in the B<-key>
argument. PEM is the default.

=item B<-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.

=item B<-nodes>

if this option is specified then if a private key is created it
will not be encrypted.

=item B<-[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 ignore for DSA requests: they always use SHA1.

=item B<-config filename>

this allows an alternative configuration file to be specified,
this overrides the compile time filename or any specified in
the B<OPENSSL_CONF> environment variable.

=item B<-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.

=item B<-days n>

when the B<-x509> option is being used this specifies the number of
days to certify the certificate for. The default is 30 days.

=item B<-extensions section>
=item B<-reqexts section>

these options specify alternative sections to include certificate
extensions (if the B<-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.

=item B<-asn1-kludge>

by default the B<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 B<Attributes> in a PKCS#10 certificate request
are defined as a B<SET OF Attribute>. They are B<not OPTIONAL> so
if no attributes are present then they should be encoded as an
empty B<SET OF>. The invalid form does not include the empty
B<SET OF> whereas the correct form does.

It should be noted that very few CAs still require the use of this option.

=back

=head1 CONFIGURATION FILE FORMAT

The configuation options are specified in the B<req> section of
the configuration file. As with all configuration files if no
value is specified in the specific section (i.e. B<req>) then
the initial unnamed or B<default> section is searched too.

The options available are described in detail below.

=over 4

=item B<default_bits>

This specifies the default key size in bits. If not specified then
512 is used. It is used if the B<-new> option is used. It can be
overriden by using the B<-newkey> option.

=item B<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
overriden by the B<-keyout> option.

=item B<oid_file>

This specifies a file containing additional B<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. 

=item B<oid_section>

This specifies a section in the configuration file containing extra
object identifiers. Each line should consist of the numerical form
of the object identifier followed by B<=> and its name. The short
and long names are the same when this option is used.

=item B<RANDFILE>

This specifies a filename in which random number seed information is
placed and read from. It is used for private key generation.

=item B<encrypt_rsa_key|encrypt_key>

If this is set to B<no> then if a private key is generated it is
B<not> encrypted. This is equivalent to the B<-nodes> command line
option.

=item B<default_md>

This option specifies the digest algorithm to use. Possible values
include B<md5 sha1 mdc2>. If not present then MD5 is used. This
option can be overridden on the command line.

=item B<dirstring_type>

This option specifies which string types are permissible in a
B<DirectoryString>. Most users will not need to change this option.

It can be set to several values B<default> which is also the default
option uses PrintableStrings, T61Strings and BMPStrings if the 
B<pkix> value is used then only PrintableStrings and BMPStrings will
be used. This follows the PKIX recommendation in RFC2459. If the
B<utf8only> option is used then only UTF8Strings will be used: this
is the PKIX recommendation in RFC2459 after 2003. Finally the B<nobmp>
option just uses PrintableStrings and T61Strings: certain software has
problems with BMPStrings.

=item B<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 B<-reqexts> command line switch.

=item B<x509_extensions>

this specifies the configuration file section containing a list of
extensions to add to certificate generated when the B<-x509> switch
is used. It can be overridden by the B<-extensions> command line switch.

=item B<attributes>

this specifies the section containing any request attributes: its format
is the same as B<distinguished_name> described below. Typically these
may contain the challengePassword or unstructuredName types. They are
currently ignored by OpenSSLs request signing utilities but some CAs might want
want them.

=item B<distinguished_name>

This specifies the section containing the distiguished name fields to
prompt for when generating a certificate or certificate request. This
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.
The "prompt" string is used to ask the user to enter the relvant
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 recognise the same name occurring twice. To avoid this problem
if the fieldName contains an 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, stateOrPrivinceName. Additionally emailAddress
is include as well as name, surname, givenName initials and dnQualifier
are supported.

Additional object identifiers can be defined with the B<oid_file> or
B<oid_section> options in the configuration file. Any additional fields
will be treated as though they were a DirectoryString.

=head1 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

=head1 NOTES

The header and footer lines in the B<PEM> format contain the words
B<BEGIN CERTIFICATE REQUEST> and B<END CERTIFICATE REQUEST> some software
(for example some versions of Netscape certificate server) requires the
words B<BEGIN NEW CERTIFICATE REQUEST> and B<END NEW CERTIFICATE REQUEST>
instead.

The certificate requests generated by B<Xenroll> with MSIE have extensions
added. It includes the B<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.

=head1 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
certficates 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 B<SET OF> structure (the DER encoding of which is 0xa0
0x00). If you just see:

        Attributes:

then the B<SET OF> is missing and the encoding is technically invalid (but
it is tolerated). See the description of the command line option B<-asn1-kludge>
for more information.

=head1 ENVIRONMENT VARIABLES

The variable B<OPENSSL_CONF> if defined allows an alternative configuration
file location to be specified, it will be overridden by the B<-config> command
line switch if it is present. For compatability reasons the B<SSLEAY_CONF>
environment variable serves the same purpose but its use is discouraged.

=head1 BUGS

OpenSSLs 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 exits if you get the strings
wrong and 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.

There should be a way to have a friendly front end (e.g. perl script or GUI)
handle all user input and then just feed a "template" file into B<req> which
then silently creates the request or certificate. This would also shift the
responsibility for handling such problems as internationalisation of characters
onto the front end: the template could then just expect valid UTF8 character
strings for example.

=head1 SEE ALSO

x509(1), ca(1), genrsa(1), gendsa(1), config(5)

=cut