MAN page from Trustix openssl-0.9.7m-1tr.i586.rpm
Section: OpenSSL (1)
req - PKCS#10 certificate request and certificate generating utility.
command primarily creates and processes certificate requestsin PKCS#10 format. It can additionally create self signed certificatesfor use as root CAs for example.
- -inform DER|PEM
- This specifies the input format. The DER option uses an ASN1 DER encodedform compatible with the PKCS#10. The PEM form is the default format: itconsists of the DER format base64 encoded with additional header andfooter 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 inputif this option is not specified. A request is only read if the creationoptions (-new and -newkey) are not specified.
- -passin arg
- the input file password source. For more information about the format of argsee the PASS PHRASE ARGUMENTS section in openssl(1).
- -out filename
- This specifies the output filename to write to or standard output bydefault.
- -passout arg
- the output file password source. For more information about the format of argsee the PASS PHRASE ARGUMENTS section in openssl(1).
- prints out the certificate request in text form.
- outputs the public key.
- this option prevents output of the encoded version of the request.
- this option prints out the value of the modulus of the public keycontained in the request.
- verifies the signature on the request.
- this option generates a new certificate request. It will promptthe user for the relevant field values. The actual fieldsprompted for and their maximum and minimum sizes are specifiedin the configuration file and any requested extensions.
If the -key option is not used it will generate a new RSA privatekey using information specified in the configuration file.
- -rand file(s)
- a file or files containing random data used to seed the random numbergenerator, 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 : forall others.
- -newkey arg
- this option creates a new certificate request and a new privatekey. The argument takes one of two forms. rsa:nbits, wherenbits is the number of bits, generates an RSA key nbitsin size. dsa:filename generates a DSA key using the parametersin the file filename.
- -key filename
- This specifies the file to read the private key from. It alsoaccepts PKCS#8 format private keys for PEM format files.
- -keyform PEM|DER
- the format of the private key file specified in the -keyargument. 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 theconfiguration file is used.
- if this option is specified then if a private key is created itwill not be encrypted.
- this specifies the message digest to sign the request with. Thisoverrides 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 inthe OPENSSL_CONF environment variable.
- -subj arg
- sets subject name for new request or supersedes the subject namewhen processing a request.The arg must be formatted as /type0=value0/type1=value1/type2=...,characters may be escaped by \ (backslash), no spaces are skipped.
- this option outputs a self signed certificate instead of a certificaterequest. This is typically used to generate a test certificate ora self signed root CA. The extensions added to the certificate(if any) are specified in the configuration file. Unless specifiedusing the set_serial option 0 will be used for the serialnumber.
- -days n
- when the -x509 option is being used this specifies the number ofdays to certify the certificate for. The default is 30 days.
- -set_serial n
- serial number to use when outputting a self signed certificate. Thismay 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 certificateextensions (if the -x509 option is present) or certificaterequest extensions. This allows several different sections tobe used in the same configuration file to specify requests fora variety of purposes.
- this option causes field values to be interpreted as UTF8 strings, by default they are interpreted as ASCII. This means that the fieldvalues, whether prompted from a terminal or obtained from aconfiguration file, must be valid UTF8 strings.
- -nameopt option
- option which determines how the subject or issuer names are displayed. Theoption argument can be a single option or multiple options separated bycommas. Alternatively the -nameopt switch may be used more than once toset multiple options. See the x509(1) manual page for details.
- by default the req command outputs certificate requests containingno attributes in the correct PKCS#10 format. However certain CAs will onlyaccept requests containing no attributes in an invalid form: thisoption produces this invalid format.
More precisely the Attributes in a PKCS#10 certificate requestare defined as a SET OF Attribute. They are not OPTIONAL soif no attributes are present then they should be encoded as anempty SET OF. The invalid form does not include the emptySET 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 outputedrequest. Some software (Netscape certificate server) and some CAs need this.
- non-interactive mode.
- print extra details about the operations being performed.
- -engine id
- specifying an engine (by it's unique id string) will cause reqto attempt to obtain a functional reference to the specified engine,thus initialising it if needed. The engine will then be set as the defaultfor all available algorithms.
CONFIGURATION FILE FORMAT
The configuration options are specified in the req
section ofthe configuration file. As with all configuration files if novalue is specified in the specific section (i.e. req
) thenthe 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) andthe output private key file (if one will be created). Thecommand line options passin and passout override theconfiguration file values.
- This specifies the default key size in bits. If not specified then512 is used. It is used if the -new option is used. It can beoverridden by using the -newkey option.
- This is the default filename to write a private key to. If notspecified the key is written to standard output. This can beoverridden by the -keyout option.
- This specifies a file containing additional OBJECT IDENTIFIERS.Each line of the file should consist of the numerical form of theobject identifier followed by white space then the short name followedby white space and finally the long name.
- This specifies a section in the configuration file containing extraobject identifiers. Each line should consist of the short name of theobject identifier followed by = and the numerical form. The shortand long names are the same when this option is used.
- This specifies a filename in which random number seed information isplaced 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 isnot encrypted. This is equivalent to the -nodes command lineoption. For compatibility encrypt_rsa_key is an equivalent option.
- This option specifies the digest algorithm to use. Possible valuesinclude md5 sha1 mdc2. If not present then MD5 is used. Thisoption can be overridden on the command line.
- This option masks out the use of certain string types in certainfields. Most users will not need to change this option.
It can be set to several values default which is also the defaultoption uses PrintableStrings, T61Strings and BMPStrings if the pkix value is used then only PrintableStrings and BMPStrings willbe used. This follows the PKIX recommendation in RFC2459. If theutf8only option is used then only UTF8Strings will be used: thisis the PKIX recommendation in RFC2459 after 2003. Finally the nombstroption just uses PrintableStrings and T61Strings: certain software hasproblems with BMPStrings and UTF8Strings: in particular Netscape.
- this specifies the configuration file section containing a list ofextensions to add to the certificate request. It can be overriddenby the -reqexts command line switch.
- this specifies the configuration file section containing a list ofextensions to add to certificate generated when the -x509 switchis used. It can be overridden by the -extensions command line switch.
- if set to the value no this disables prompting of certificate fieldsand just takes values from the config file directly. It also changes theexpected format of the distinguished_name and attributes sections.
- if set to the value yes then field values to be interpreted as UTF8strings, by default they are interpreted as ASCII. This means thatthe field values, whether prompted from a terminal or obtained from aconfiguration file, must be valid UTF8 strings.
- this specifies the section containing any request attributes: its formatis the same as distinguished_name. Typically these may contain thechallengePassword or unstructuredName types. They are currently ignoredby OpenSSL's request signing utilities but some CAs might want them.
- This specifies the section containing the distinguished name fields toprompt for when generating a certificate or certificate request. The formatis described in the next section.
DISTINGUISHED NAME AND ATTRIBUTE SECTION FORMAT
There are two separate formats for the distinguished name and attributesections. If the prompt
option is set to no
then these sectionsjust consist of field names and values: for example,
CN=My Name OU=My Organization emailAddress=someoneAATTsomewhere.org
This allows external programs (e.g. GUI based) to generate a template filewith all the field names and values and just pass it to req. An exampleof this kind of configuration file is contained in the EXAMPLES section.
Alternatively if the prompt option is absent or not set to no then thefile 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 relevantdetails. If the user enters nothing then the default value is used if nodefault value is present then the field is omitted. A field canstill be omitted if a default value is present if the user justenters the '.' character.
The number of characters entered must be between the fieldName_min andfieldName_max limits: there may be additional restrictions basedon the field being used (for example countryName can only ever betwo characters long and must fit in a PrintableString).
Some fields (such as organizationName) can be used more than oncein a DN. This presents a problem because configuration files willnot recognize the same name occurring twice. To avoid this problemif the fieldName contains some characters followed by a full stopthey will be ignored. So for example a second organizationName canbe input by calling it ``1.organizationName''.
The actual permitted field names are any object identifier short orlong names. These are compiled into OpenSSL and include the usualvalues such as commonName, countryName, localityName, organizationName,organizationUnitName, stateOrProvinceName. Additionally emailAddressis include as well as name, surname, givenName initials and dnQualifier.
Additional object identifiers can be defined with the oid_file oroid_section options in the configuration file. Any additional fieldswill be treated as though they were a DirectoryString.
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:
18.104.22.168 shortName A longer Name 22.214.171.124 otherName Other longer Name
Example of a section pointed to by oid_section making use of variableexpansion:
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 = testAATTemail.address
[ req_attributes ] challengePassword = A challenge password
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 extensionsadded. It includes the keyUsage extension which determines the type ofkey (signature only or general purpose) and any additional OIDs enteredby the script in an extendedKeyUsage extension.
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 configurationfile! Certain operations (like examining a certificate request) don'tneed a configuration file so its use isn't enforced. Generation ofcertificates or requests however does need a configuration file. Thiscould be regarded as a bug.
Another puzzling message is this:
this is displayed when no attributes are present and the request includesthe correct empty SET OF structure (the DER encoding of which is 0xa00x00). If you just see:
then the SET OF is missing and the encoding is technically invalid (butit is tolerated). See the description of the command line option -asn1-kludgefor more information.
The variable OPENSSL_CONF
if defined allows an alternative configurationfile location to be specified, it will be overridden by the -config
commandline switch if it is present. For compatibility reasons the SSLEAY_CONF
environment variable serves the same purpose but its use is discouraged.
OpenSSL's handling of T61Strings (aka TeletexStrings) is broken: it effectivelytreats 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 inPrintableStrings and you don't want to or can't use BMPStrings.
As a consequence of the T61String handling the only correct way to representaccented characters in OpenSSL is to use a BMPString: unfortunately Netscapecurrently chokes on these. If you have to use accented characters with Netscapeand 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 whatyou've just entered. Other things like extensions in certificate requests arestatically defined in the configuration file. Some of these: like an emailaddress in subjectAltName should be input by the user.
- COMMAND OPTIONS
- CONFIGURATION FILE FORMAT
- DISTINGUISHED NAME AND ATTRIBUTE SECTION FORMAT
- ENVIRONMENT VARIABLES
- SEE ALSO
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