Generates a CSR

# openssl_csr_new

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

openssl_csr_new — Generates a CSR

### Description

openssl_csr_new(
array `$distinguished_names`,
#[\SensitiveParameter] ?OpenSSLAsymmetricKey `&$private_key`,
?array `$options` = `null`,
?array `$extra_attributes` = `null`
): OpenSSLCertificateSigningRequest|bool

openssl_csr_new() generates a new CSR based on the information provided by `distinguished_names`.

> Note: You need to have a valid openssl.cnf installed for this function to operate correctly. See the notes under the installation section for more information.

### Parameters

`distinguished_names`

  The Distinguished Name or subject fields to be included in the certificate. The `distinguished_names` is an associative array where the keys represent the attribute names of Distinguished Names and the values can either be strings (for single value) or arrays (if multiple values need to be set).

`private_key`

  `private_key` should be set to a private key that was previously generated by openssl_pkey_new() (or otherwise obtained from the other openssl_pkey family of functions), or `null` variable. If its value is `null` variable, a new private key is generated based on the supplied `options` and assigned to supplied variable. The corresponding public portion of the key will be used to sign the CSR.

`options`

  By default, the information in your system `openssl.conf` is used to initialize the request; you can specify a configuration file section by setting the `config_section_section` key in `options`. You can also specify an alternative OpenSSL configuration file by setting the value of the `config` key to the path of the file you want to use. The following keys, if present in `options` behave as their equivalents in the `openssl.conf`, as listed in the table below.

  Configuration overrides
  `options` key | type | `openssl.conf` equivalent | description
  --- | --- | --- | ---
  digest_alg | string | default_md | Digest method or signature hash, usually one of openssl_get_md_methods()
  x509_extensions | string | x509_extensions | Selects which extensions should be used when creating an x509 certificate
  req_extensions | string | req_extensions | Selects which extensions should be used when creating a CSR
  private_key_bits | int | default_bits | Specifies how many bits should be used to generate a private key
  private_key_type | int | none | Specifies the type of private key to create. This can be one of `OPENSSL_KEYTYPE_DSA`, `OPENSSL_KEYTYPE_DH`, `OPENSSL_KEYTYPE_RSA` or `OPENSSL_KEYTYPE_EC`. The default value is `OPENSSL_KEYTYPE_RSA`.
  encrypt_key | bool | encrypt_key | Should an exported key (with passphrase) be encrypted?
  encrypt_key_cipher | int | none | One of cipher constants.
  curve_name | string | none | One of openssl_get_curve_names().
  config | string | N/A | Path to your own alternative openssl.conf file.

`extra_attributes`

  `extra_attributes` is used to specify additional attributes for the CSR. It is an associative arrays where the keys are converted to OIDs and applied as CSR attributes.

### Return Values

Returns the CSR on success, `true` if CSR creation is successful but signing fails or `false` on failure.

### Changelog

Version | Description
--- | ---
8.4.0 | The `distinguished_names` associative array now supports arrays as values, allowing multiple values to be specified for a single attribute.
8.4.0 | The `extra_attributes` parameter now correctly sets the CSR attributes, rather than modifying the subject's Distinguished Name as it previously did incorrectly.
8.0.0 | On success, this function returns an OpenSSLCertificateSigningRequest instance now; previously, a resource of type `OpenSSL X.509 CSR` was returned.
8.0.0 | `private_key` accepts an OpenSSLAsymmetricKey instance now; previously, a resource of type `OpenSSL key` was accepted.
7.1.0 | `options` now also supports `curve_name`.

### Examples

Example #1 Creating a self-signed certificate

`<?php
// for SSL server certificates the commonName is the domain name to be secured
// for S/MIME email certificates the commonName is the owner of the email address
// location and identification fields refer to the owner of domain or email subject to be secured
$dn = array(
"countryName" => "GB",
"stateOrProvinceName" => "Somerset",
"localityName" => "Glastonbury",
"organizationName" => "The Brain Room Limited",
"organizationalUnitName" => "PHP Documentation Team",
"commonName" => "Wez Furlong",
"emailAddress" => "wez@example.com"
);
// Generate a new private (and public) key pair
$privkey = openssl_pkey_new(array(
"private_key_bits" => 2048,
"private_key_type" => OPENSSL_KEYTYPE_RSA,
));
// Generate a certificate signing request
$csr = openssl_csr_new($dn, $privkey, array('digest_alg' => 'sha256'));
// Generate a self-signed cert, valid for 365 days
$x509 = openssl_csr_sign($csr, null, $privkey, $days=365, array('digest_alg' => 'sha256'));
// Save your private key, CSR and self-signed cert for later use
openssl_csr_export($csr, $csrout) and var_dump($csrout);
openssl_x509_export($x509, $certout) and var_dump($certout);
openssl_pkey_export($privkey, $pkeyout, "mypassword") and var_dump($pkeyout);
// Show any errors that occurred here
while (($e = openssl_error_string()) !== false) {
echo $e . "\n";
}
?>`

Example #2 Creating a self-signed ECC certificate (as of PHP 7.1.0)

`<?php
$subject = array(
"commonName" => "docs.php.net",
);
// Generate a new private (and public) key pair
$private_key = openssl_pkey_new(array(
"private_key_type" => OPENSSL_KEYTYPE_EC,
"curve_name" => 'prime256v1',
));
// Generate a certificate signing request
$csr = openssl_csr_new($subject, $private_key, array('digest_alg' => 'sha384'));
// Generate self-signed EC cert
$x509 = openssl_csr_sign($csr, null, $private_key, $days=365, array('digest_alg' => 'sha384'));
openssl_x509_export_to_file($x509, 'ecc-cert.pem');
openssl_pkey_export_to_file($private_key, 'ecc-private.key');
?>`

### See Also

- openssl_csr_sign() - Sign a CSR with another certificate (or itself) and generate a certificate

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