man > openssl-req(1)

TLDR: openssl-req (tldr-pages)

Manage PKCS#10 Certificate Signing Requests.

  • Generate a certificate signing request to be sent to a certificate authority
    openssl req -new -sha256 -key {{filename.key}} -out {{filename.csr}}
  • Generate a self-signed certificate and a corresponding key-pair, storing both in a file
    openssl req -new -x509 -newkey {{rsa}}:{{4096}} -keyout {{filename.key}} -out {{filename.cert}} -subj "{{/C=XX/CN=foobar}}" -days {{365}}
OPENSSL-REQ(1SSL)                              OpenSSL                             OPENSSL-REQ(1SSL)

NAME
       openssl-req - PKCS#10 certificate request and certificate generating command

SYNOPSIS
       openssl req [-help] [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-passin arg] [-out
       filename] [-passout arg] [-text] [-pubkey] [-noout] [-verify] [-modulus] [-new] [-newkey arg]
       [-pkeyopt opt:value] [-noenc] [-nodes] [-key filename|uri] [-keyform DER|PEM|P12|ENGINE]
       [-keyout filename] [-keygen_engine id] [-digest] [-config filename] [-section name] [-x509]
       [-CA filename|uri] [-CAkey filename|uri] [-days n] [-set_serial n] [-newhdr]
       [-copy_extensions arg] [-addext ext] [-extensions section] [-reqexts section] [-precert]
       [-utf8] [-reqopt] [-subject] [-subj arg] [-multivalue-rdn] [-sigopt nm:v] [-vfyopt nm:v]
       [-batch] [-verbose] [-nameopt option] [-rand files] [-writerand file] [-engine id] [-provider
       name] [-provider-path path] [-propquery propq]

DESCRIPTION
       This command primarily creates and processes certificate requests (CSRs) in PKCS#10 format.
       It can additionally create self-signed certificates for use as root CAs for example.

OPTIONS
       -help
           Print out a usage message.

       -inform DER|PEM, -outform DER|PEM
           The  input and output formats; unspecified by default.  See openssl-format-options(1) for
           details.

           The data is a PKCS#10 object.

       -in filename
           This specifies the input filename to read a request  from.   This  defaults  to  standard
           input  unless  -x509 or -CA is specified.  A request is only read if the creation options
           (-new or -newkey or -precert) are not specified.

       -sigopt nm:v
           Pass options to the signature algorithm during sign  operations.   Names  and  values  of
           these options are algorithm-specific.

       -vfyopt nm:v
           Pass  options  to  the signature algorithm during verify operations.  Names and values of
           these options are algorithm-specific.

       -passin arg
           The password source for private key and certificate input.  For  more  information  about
           the format of arg see openssl-passphrase-options(1).

       -passout arg
           The  password  source  for the output file.  For more information about the format of arg
           see openssl-passphrase-options(1).

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

       -text
           Prints out the certificate request in text form.

       -subject
           Prints out the certificate request subject (or certificate subject if -x509 is in use).

       -pubkey
           Prints out the public key.

       -noout
           This option prevents output of the encoded version of the certificate request.

       -modulus
           Prints out the value of the modulus of the public key contained in the request.

       -verify
           Verifies the self-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 given it will generate a new private key using information
           specified in the configuration file or given with the -newkey and -pkeyopt options,  else
           by default an RSA key with 2048 bits length.

       -newkey arg
           This  option  is  used  to  generate  a  new  private  key  unless  -key is given.  It is
           subsequently used as if it was given using the -key option.

           This option implies the  -new  flag  to  create  a  new  certificate  request  or  a  new
           certificate in case -x509 is given.

           The argument takes one of several forms.

           [rsa:]nbits  generates  an RSA key nbits in size.  If nbits is omitted, i.e., -newkey rsa
           is specified, the  default  key  size  specified  in  the  configuration  file  with  the
           default_bits option is used if present, else 2048.

           All  other  algorithms  support the -newkey algname:file form, where file is an algorithm
           parameter file, created with "openssl genpkey -genparam" or an X.509  certificate  for  a
           key with appropriate algorithm.

           param:file generates a key using the parameter file or certificate file, the algorithm is
           determined by the parameters.

           algname[:file]  generates  a  key using the given algorithm algname.  If a parameter file
           file is given  then  the  parameters  specified  there  are  used,  where  the  algorithm
           parameters  must  match  algname.   If  algorithm parameters are not given, any necessary
           parameters should be specified via the -pkeyopt option.

           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 gost 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 openssl-genpkey(1) for more details.

       -key filename|uri
           This option provides the private  key  for  signing  a  new  certificate  or  certificate
           request.   Unless  -in  is  given,  the  corresponding  public  key  is placed in the new
           certificate or certificate request, resulting in a self-signature.

           For certificate signing this option is overridden by the -CA option.

           This option also accepts PKCS#8 format private keys for PEM format files.

       -keyform DER|PEM|P12|ENGINE
           The format of the private key; unspecified by default.  See openssl-format-options(1) for
           details.

       -keyout filename
           This gives the filename to write any private key to that has been newly created  or  read
           from -key.  If neither the -keyout option nor the -key option are given then the filename
           specified  in the configuration file with the default_keyfile option is used, if present.
           Thus, if you want to write the private key and the -key option is  provided,  you  should
           provide  the  -keyout  option  explicitly.   If a new key is generated and no filename is
           specified the key is written to standard output.

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

       -nodes
           This option is deprecated since OpenSSL 3.0; use -noenc instead.

       -digest
           This specifies the message digest to sign the  request.   Any  digest  supported  by  the
           OpenSSL  dgst  command can be used.  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), Ed25519 and
           Ed448 never use any digest.

       -config filename
           This allows  an  alternative  configuration  file  to  be  specified.   Optional;  for  a
           description of the default value, see "COMMAND SUMMARY" in openssl(1).

       -section name
           Specifies the name of the section to use; the default is req.

       -subj arg
           Sets  subject  name  for  new  request  or  supersedes the subject name when processing a
           certificate request.

           The arg must be formatted as "/type0=value0/type1=value1/type2=...".  Special  characters
           may  be  escaped by "\" (backslash), whitespace is retained.  Empty values are permitted,
           but the corresponding type will not be included in the request.  Giving a single "/" will
           lead to an empty sequence of RDNs (a  NULL-DN).   Multi-valued  RDNs  can  be  formed  by
           placing a "+" character instead of a "/" between the AttributeValueAssertions (AVAs) that
           specify the members of the set.  Example:

           "/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe"

       -multivalue-rdn
           This option has been deprecated and has no effect.

       -x509
           This  option  outputs  a certificate instead of a certificate request.  This is typically
           used to generate test certificates.  It is implied by the -CA option.

           This option implies the -new flag if -in is not given.

           If an existing  request  is  specified  with  the  -in  option,  it  is  converted  to  a
           certificate; otherwise a request is created from scratch.

           Unless specified using the -set_serial option, a large random number will be used for the
           serial number.

           Unless  the  -copy_extensions  option  is  used, X.509 extensions are not copied from any
           provided request input file.

           X.509 extensions to be added can be specified in the  configuration  file  or  using  the
           -addext option.

       -CA filename|uri
           Specifies  the  "CA" certificate to be used for signing a new certificate and implies use
           of -x509.  When present, this behaves like a "micro CA" as follows: The subject  name  of
           the  "CA"  certificate  is  placed  as  issuer name in the new certificate, which is then
           signed using the "CA" key given as specified below.

       -CAkey filename|uri
           Sets the "CA" private key to sign a certificate with.  The private  key  must  match  the
           public  key  of  the certificate given with -CA.  If this option is not provided then the
           key must be present in the -CA input.

       -days n
           When -x509 is in use this specifies the number of days to certify  the  certificate  for,
           otherwise it is ignored. n should be a positive integer. 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".  If not given, a large random number
           will be used.

       -copy_extensions arg
           Determines how X.509 extensions in certificate requests should be handled when  -x509  is
           in  use.   If  arg is none or this option is not present then extensions are ignored.  If
           arg is copy or copyall then all extensions in the request are copied to the certificate.

           The main use of this option is to allow  a  certificate  request  to  supply  values  for
           certain extensions such as subjectAltName.

       -addext ext
           Add  a specific extension to the certificate (if -x509 is in use) or certificate request.
           The argument must have the form of a key=value pair as it would appear in a config file.

           This option can be given multiple times.

       -extensions section
       -reqexts section
           These options specify alternative sections to include certificate extensions (if -x509 is
           in use) 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.

       -precert
           A  poison  extension will be added to the certificate, making it a "pre-certificate" (see
           RFC6962). This can be submitted to Certificate  Transparency  logs  in  order  to  obtain
           signed  certificate  timestamps  (SCTs).   These  SCTs can then be embedded into the pre-
           certificate as an extension, before removing the poison and signing the certificate.

           This implies the -new flag.

       -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.

       -reqopt option
           Customise the printing format used with -text. The option argument can be a single option
           or multiple options separated by commas.

           See discussion of the  -certopt parameter in the openssl-x509(1) command.

       -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.

       -keygen_engine id
           Specifies  an  engine  (by  its  unique id string) which would be used for key generation
           operations.

       -nameopt option
           This   specifies   how   the   subject   or   issuer   names    are    displayed.     See
           openssl-namedisplay-options(1) for details.

       -rand files, -writerand file
           See "Random State Options" in openssl(1) for details.

       -engine id
           See "Engine Options" in openssl(1).  This option is deprecated.

       -provider name
       -provider-path path
       -propquery propq
           See "Provider Options" in openssl(1), provider(7), and property(7).

CONFIGURATION FILE FORMAT
       The  configuration  options  are  specified  in the req section of the configuration file. An
       alternate name be specified by using the -section option.  As with all  configuration  files,
       if  no value is specified in the specific section 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
           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.

       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 whitespace then
           the short name followed by whitespace 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
           At startup the specified file is loaded into the random number generator, and at exit 256
           bytes will be written to it.  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  -noenc  command line option. For compatibility encrypt_rsa_key is an
           equivalent option.

       default_md
           This option specifies the digest algorithm to use. Any digest supported  by  the  OpenSSL
           dgst  command  can  be  used.  This option can be overridden on the command line. Certain
           signing algorithms (i.e. Ed25519 and Ed448) will ignore any digest that has been set.

       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 -x509 is in use.  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.

DISTINGUISHED NAME AND ATTRIBUTE SECTION FORMAT
       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 AT 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 this command. 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 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.

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 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

       Create an SM2 private key and then generate a certificate request from it:

        openssl ecparam -genkey -name SM2 -out sm2.key
        openssl req -new -key sm2.key -out sm2.csr -sm3 -sigopt "distid:1234567812345678"

       Examine and verify an SM2 certificate request:

        openssl req -verify -in sm2.csr -sm3 -vfyopt "distid:1234567812345678"

       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           = 2048
        default_keyfile        = privkey.pem
        distinguished_name     = req_distinguished_name
        attributes             = req_attributes
        req_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 = critical, CA:true

       Sample configuration containing all field values:

        [ 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 AT email.address

        [ req_attributes ]
        challengePassword              = A challenge password

       Example of giving the most common attributes (subject and extensions) on the command line:

        openssl req -new -subj "/C=GB/CN=foo" \
                         -addext "subjectAltName = DNS:foo.co.uk" \
                         -addext "certificatePolicies = 1.2.3.4" \
                         -newkey rsa:2048 -keyout key.pem -out req.pem

NOTES
       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.

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

HISTORY
       The -section option was added in OpenSSL 3.0.0.

       The -multivalue-rdn option has become obsolete in OpenSSL 3.0.0 and has no effect.

       The  -engine  option  was  deprecated  in OpenSSL 3.0.  The <-nodes> option was deprecated in
       OpenSSL 3.0, too; use -noenc instead.

COPYRIGHT
       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file  except  in
       compliance  with  the  License.   You  can  obtain  a  copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.

3.0.13                                       2026-07-29                            OPENSSL-REQ(1SSL)
openssl-req(1)
NAME SYNOPSIS DESCRIPTION OPTIONS
-help -inform DER|PEM, -outform DER|PEM -in filename -sigopt nm:v -vfyopt nm:v -passin arg -passout arg -out filename -text -subject -pubkey -noout -modulus -verify -new -newkey arg -pkeyopt opt:value -key filename|uri -keyform DER|PEM|P12|ENGINE -keyout filename -noenc -nodes -digest -config filename -section name -subj arg -multivalue-rdn -x509 -CA filename|uri -CAkey filename|uri -days n -set_serial n -copy_extensions arg -addext ext -extensions section -reqexts section -precert -utf8 -reqopt option -newhdr -batch -verbose -keygen_engine id -nameopt option -rand files, -writerand file -engine id -provider name -provider-path path -propquery propq
CONFIGURATION FILE FORMAT
default_bits default_keyfile oid_file oid_section encrypt_key default_md string_mask req_extensions x509_extensions prompt utf8 attributes distinguished_name
DISTINGUISHED NAME AND ATTRIBUTE SECTION FORMAT EXAMPLES NOTES DIAGNOSTICS BUGS SEE ALSO HISTORY COPYRIGHT

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