req - PKCS#10 certificate request and certificate generating utility.


   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]
   [-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]


   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.


   -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).

       prints out the certificate request in text form.

       prints out the request subject (or certificate subject if -x509 is

       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 key
       contained in the request.

       verifies the signature on the request.

       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

       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.

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

       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.

       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.

       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, a large random number
       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

       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.

       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.

       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

       Reverses effect of -asn1-kludge

       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.

       non-interactive mode.

       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.

       Specifies the default key size in bits.

       This option is used in conjunction with the -new option to generate
       a new key. It can be overridden by specifying an explicit key size
       in the -newkey option. The smallest accepted key size is 512 bits.
       If no key size is specified then 2048 bits is used.

       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.

       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.

       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.

       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.

       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.

       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.

       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

       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.

       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.

       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.

       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.

       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.

       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

   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

   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

    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

   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.


   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 2048
    openssl req -new -key key.pem -out req.pem

   The same but just using req:

    openssl req -newkey rsa:2048 -keyout key.pem -out req.pem

   Generate a self signed root certificate:

    openssl req -x509 -newkey rsa:2048 -keyout key.pem -out req.pem

   Example of a file pointed to by the oid_file option:        shortName       A longer Name        otherName       Other longer Name

   Example of a section pointed to by oid_section making use of variable


   Sample configuration file prompting for field values:

    [ req ]
    default_bits           = 2048
    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 ]

    basicConstraints = CA:true

   Sample configuration containing all field values:

    RANDFILE               = $ENV::HOME/.rnd

    [ req ]
    default_bits           = 2048
    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


   The header and footer lines in the PEM format are normally:


   some software (some versions of Netscape certificate server) instead


   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.


   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.


   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.


   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

   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.


   x509(1), ca(1), genrsa(1), gendsa(1), config(5), x509v3_config(5)

More Linux Commands

keyctl_negate(3) - Negatively instantiate a key (Man Page)
keyctl_assume_authority() assumes the authority for the calling thread to deal with and instantiate the specified uninstantiated key. The calling thread must ha

Tcl_ScanElement(3) - manipulate Tcl lists - Linux man page
These procedures may be used to disassemble and reassemble Tcl lists. Tcl_SplitList breaks a list up into its constituent elements, returning an array of pointe

complex(5) - basics of complex mathematics - Linux man page
complex.5 - Complex numbers are numbers of the form z = a+b*i, where a and b are real numbers and i = sqrt(-1), so that i*i = -1. There are other ways to repres

sd_notify(3) - Notify init system about start-up completion
sd_notify() shall be called by a daemon to notify the init system about status changes. It can be used to send arbitrary information, encoded in an environment-

pcre_fullinfo(3) - Perl-compatible regular expressions......
This function returns information about a compiled pattern. Its arguments are: code Compiled regular expression extra Result of pcre[16|32]_study() or NULL what

curl_share_cleanup(3) - Clean up a shared object (Man Page)
This function deletes a shared object. The share handle cannot be used anymore when this function has been called. RETURN VALUE CURLSHE_OK (zero) means that the

pamendian(1) - reverse endianness of a Netpbm image.........
This program is part of Netpbm(1) All Netpbm formats that have samples in pure binary format with multiple bytes are defined to have them in big endian (most si

LWP::Debug(3pm) - deprecated (Library - Linux man page).....
LWP::Debug used to provide tracing facilities, but these are not used by LWP any more. The code in this module is kept around (undocumented) so that 3rd party c

mrtg-nt-guide(1) The MRTG 2.17.4 Windows Installation Guide
To get MRTG to work on Windows you need the following: A current copy of Perl. For Example ActivePerl 5.8.8 from ActiveState, the latest version of MRTG from...

mvwinwstr(3ncurses) - get a string of wchar_t characters fro
These routines return a string of wchar_t characters in wstr, extracted starting at the current cursor position in the named window. Attributes are stripped fro

git-cvsimport(1) Salvage your data out of another SCM people
WARNING: git cvsimport uses cvsps version 2, which is considered deprecated; it does not work with cvsps version 3 and later. If you are performing a one-shot i

endspent(3) - get shadow password file entry (Man Page).....
Long ago it was considered safe to have encrypted passwords openly visible in the password file. When computers got faster and people got more security-consciou

We can't live, work or learn in freedom unless the software we use is free.