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

openssl_csr_newGenerates a CSR


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

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

Nota: É preciso ter um arquivo openssl.cnf válido instalado para que esta função funcione corretamente. Consulte as notas na seção de instalação para obter mais informações.



The Distinguished Name or subject fields to be used in the certificate.


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). The corresponding public portion of the key will be used to sign the CSR.


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 of 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 is used to specify additional configuration options for the CSR. Both distinguished_names and extra_attributes are associative arrays whose keys are converted to OIDs and applied to the relevant part of the request.

Valor Retornado

Returns the CSR ou false em caso de falha.

Registro de Alterações

Versão Descrição
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.


Exemplo #1 Creating a self-signed certificate

// 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" => ""

// 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) {
$e . "\n";

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

= array(
"commonName" => "",

// 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');

Veja Também

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

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User Contributed Notes 10 notes

14 years ago
Not sure whether the "bug" (undocumented behavior) I encountered is common to other people, but this comment might save hours of painful debug:
If you can't generate a new private key using openssl_pkey_new() or openssl_csr_new(), your script hangs during the call of these functions and in case you specified a "private_key_bits" parameter, ensure that you cast the variable to an int. Took me ages to notice that.

= array('config' => '/usr/local/nessy2/share/ssl/openssl.cnf',
'encrypt_key' => true,
'private_key_type' => OPENSSL_KEYTYPE_RSA,
'digest_alg' => 'sha1',
'x509_extensions' => 'v3_ca',
'private_key_bits' => $someVariable // ---> bad
'private_key_bits' => (int)$someVariable // ---> good
'private_key_bits' => 512 // ---> obviously good
james at kirk dot com
9 years ago
When in doubt, read the source code to PHP!

$configargs is fairly opaque as to what is going on behind the scenes. That is, until you actually look at php_openssl_parse_config() in '/ext/openssl/openssl.c':

SET_OPTIONAL_STRING_ARG("digest_alg", req->digest_name,
CONF_get_string(req->req_config, req->section_name, "default_md"));
SET_OPTIONAL_STRING_ARG("x509_extensions", req->extensions_section,
CONF_get_string(req->req_config, req->section_name, "x509_extensions"));
SET_OPTIONAL_STRING_ARG("req_extensions", req->request_extensions_section,
CONF_get_string(req->req_config, req->section_name, "req_extensions"));
SET_OPTIONAL_LONG_ARG("private_key_bits", req->priv_key_bits,
CONF_get_number(req->req_config, req->section_name, "default_bits"));

SET_OPTIONAL_LONG_ARG("private_key_type", req->priv_key_type, OPENSSL_KEYTYPE_DEFAULT);

Here we can see that SET_OPTIONAL_STRING_ARG() is called for most inputs but for 'private_key_bits' SET_OPTIONAL_LONG_ARG() is called. Both calls are C macros that expand to code that enforces the expected input type. The generated code ignores the input without warning/notice if an unexpected type is used and just uses the default from the configuration file. This is why using a string with 'private_key_bits' will result in unexpected behavior.

Further inspection of the earlier initialization in the same function:

SET_OPTIONAL_STRING_ARG("config", req->config_filename, default_ssl_conf_filename);
SET_OPTIONAL_STRING_ARG("config_section_name", req->section_name, "req");
req->global_config = CONF_load(NULL, default_ssl_conf_filename, NULL);
req->req_config = CONF_load(NULL, req->config_filename, NULL);

if (req->req_config == NULL) {
return FAILURE;

And elsewhere in another function:

/* default to 'openssl.cnf' if no environment variable is set */
if (config_filename == NULL) {
snprintf(default_ssl_conf_filename, sizeof(default_ssl_conf_filename), "%s/%s",
} else {
strlcpy(default_ssl_conf_filename, config_filename, sizeof(default_ssl_conf_filename));

Reveals that 'config' in $configargs is an override for any default setting elsewhere. This actually negates the comment in the documentation that says "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." A more correct sentence would be "Note: You need to either have a valid openssl.cnf set up or use $configargs to point at a valid openssl.cnf file for this function to operate correctly."

All of that goes to show that looking at the PHP source code is the only real way to figure out what is actually happening. Doing so saves time and effort.
9 years ago
For those of you using Debian-based systems, the openssl configuration file is at: /etc/ssl/openssl.cnf
main ATT jokester DOTT fr
15 years ago
To set the "basicConstraints" to "critical,CA:TRUE", you have to define configargs, but in the openssl_csr_sign() function !

That's my example of code to sign a "child" certificate :

$CAcrt = "file://ca.crt";
$CAkey = array("file://ca.key", "myPassWord");

$clientKeys = openssl_pkey_new();
$dn = array(
"countryName" => "FR",
"stateOrProvinceName" => "Finistere",
"localityName" => "Plouzane",
"organizationName" => "Ecole Nationale d'Ingenieurs de Brest",
"organizationalUnitName" => "Enib Students",
"commonName" => "",
"emailAddress" => ""
$csr = openssl_csr_new($dn, $clientPrivKey);

$configArgs = array("x509_extensions" => "v3_req");
$cert = openssl_csr_sign($csr, $CAcrt, $CAkey, 100, $configArgs);

openssl_x509_export_to_file($cert, "childCert.crt");

Then if you want to add some more options, you can edit the "/etc/ssl/openssl.cnf" ssl config' file (debian path), and add these after the [ v3_req ] tag.
alex at nodex dot co dot uk
9 years ago
In the PHP example above it uses "UK" as the country name which is incorrect, the country name must be "GB"
Richard Lynch
10 years ago
There appears to be no openssl_csr_free function.

At least not here.

If it's in the source, one might be able to just call it.

If it's not in the source, it probably should be.
18 years ago
If you get the error:

error:0D11A086:asn1 encoding routines:ASN1_mbstring_copy:string too short

then look at your key:value pairs in the $dn (distinguished name) array.

If you have one value (like "organizationalUnitName" = "") set to an empty string, it will throw the above error.

Fix the error by either eliminating that array element from $dn completely, or using a space " " instead of an empty string.
robertliu AT wiscore DOT com
19 years ago
I am using PHP-4.3.11.
The type of configargs--private_key_bits is a INTEGER, not a string.
An example of configration:
= array(
"digest_alg" => "sha1",
"private_key_bits" => 2048,
"private_key_type" => OPENSSL_KEYTYPE_DSA,
"encrypt_key" => false
dankybastard at hotmail
19 years ago
As you probably guessed from the example, the documentation is misinforming. openssl_csr_new returns a CSR resource or FALSE on failure.

mixed openssl_csr_new (assoc_array dn, resource_privkey, [...])
7 years ago
One command to create modern certificate request with 4 SAN subdomain.
According to RFC you can change CN (common name) and subjectAltName. When cert validated searching in CN and subjectAltName.

openssl req -new -nodes -config <( cat <<-EOF
default_bits = 2048
prompt = no
default_md = sha256
req_extensions = re
distinguished_name = dn
[ dn ]
CN = my.tld
C = country
ST = state
L = location
[ re ]
subjectAltName = DNS.1:, DNS.2:, DNS.3:, DNS.4:
) -keyout secret.key -out req.csr
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