PHP 8.1.28 Released!


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

openssl_csr_new生成一个 CSR


    array $distinguished_names,
    OpenSSLAsymmetricKey &$private_key,
    ?array $options = null,
    ?array $extra_attributes = null
): OpenSSLCertificateSigningRequest|false

openssl_csr_new() 根据 distinguished_names 提供的信息生成新的 CSR(证书签名请求)。

注意: 必须安装有效的 openssl.cnf 以保证此函数正确运行。参考有关安装的说明以获得更多信息。





private_key 应该被设置为由 openssl_pkey_new() 函数预先生成(或者以其他方式从 openssl_pkey 函数集中获得)的私钥。该密钥的相应公共部分将用于签署 CSR


默认通过系统里的 openssl.conf 配置来初始化请求;可以通过设置 optionsconfig_section_section 项来指定配置文件部分。 还可以通过将 config 键的值设置为想要使用的文件路径来指定另一个 openssl 配置文件。如果在 options 中存在下列键,它们的行为就像在 openssl.conf 中一样。如下表所示:

options 类型 等同于 openssl.conf 描述
digest_alg string default_md 摘要算法或签名哈希算法,通常是 openssl_get_md_methods() 之一。
x509_extensions string x509_extensions 选择在创建 x509 证书时应该使用哪些扩展
req_extensions string req_extensions 创建 CSR 时,选择使用哪个扩展
private_key_bits int default_bits 指定应该使用多少位来生成私钥
encrypt_key bool encrypt_key 是否应该对导出的密钥(带有密码短语)进行加密?
encrypt_key_cipher int none cipher constants 常量之一。
curve_name string none openssl_get_curve_names() 之一。
config string N/A 自定义 openssl.conf 文件的路径。


extra_attributes 用于为 CSR 指定额外的配置选项。distinguished_namesextra_attributes 都是关联数组它们的键被转换成 OID,并应用到请求的相关部分。


成功,返回 CSR 或者在失败时返回 false


版本 说明
8.0.0 成功时,此函数现在返回 OpenSSLCertificateSigningRequest 实例;之前返回类型 OpenSSL X.509 CSRresource
8.0.0 private_key 现在接受 OpenSSLAsymmetricKey 实例;之前接受类型 OpenSSL keyresource
7.1.0 options 现在也支持 curve_name


示例 #1 创建一个自签名的证书

// 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";

示例 #2 创建一个自签名的 ECC 证书(从 PHP 7.1.0 开始)

= 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');


  • openssl_csr_sign() - 用另一个证书签署 CSR(或者本身)并且生成一个证书

add a note

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
8 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
18 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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