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" => "[email protected]"
);

// 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');
?>