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Usage and Example of PHP openssl_pkey_new() Function

The openssl_pkey_new() function is used to generate a new private key.

Definition and Usage

openssl_pkey_new() generates a new private key and public key pair. You can obtain the public component of the key through the openssl_pkey_get_public() function.

The function openssl_pkey_new() returns a resource identifier. You can use the openssl_pkey_get_details() function to get all the details of the generated key. The key (public)/The private key pair) is used later together with other openssl functions (such as openssl_sign(), openssl_csr_new())-Obtain a CSR certificate that helps create encrypted digital signatures.

Syntax

openssl_pkey_new ([ array $configargs ] ) : resource

Parameters

Number	Parameters	Description
1	configargs	You can use the configargs parameter to fine-tune the key generation (such as specifying the number of digits). Check openssl_csr_new() for more information about configargs.

Configuration parameters

By default, openssl_pkey_new() uses the configuration details that exist in openssl.cnf. However, configargs can override them. The configuration details are as follows:

configargs	Type	The key types used in openssl.conf	Description
digest_alg	String	default_md	The digest method you get from openssl_get_md_methods().
x509_extensions	String	x509_extensions	Create x509The extension name used when creating a certificate.
req_extensions	String	req_extensions	The extension name used when creating CSR.
private_key_bits	integer	default_bits	Specify the number of bits to be used when generating the private key.
private_key_type	integer	none	The type of private key to be created. It 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	Boolean	encrypt_key	Is the exported key encrypted?
encrypt_key_cipher	integer	none	Password constants, such as OPENSSL_CIPHER_RC2_40 (integer), OPENSSL_CIPHER_RC2_128(integer), OPENSSL_CIPHER_RC2_64_ (integer), OPENSSL_CIPHER_RC3DES (integer), OPENSSL_CIPHER_DES (integer), OPENSSL_CIPHER_
curve_name	String	none	One of the curve names returned by the function openssl_get_curve_names().
config	String	N/A	You can change the configuration in openssl.conf as needed and provide its path here.

Return value

If there is no error, the PHP openssl_pkey_new() function will return a resource identifier. If the key generation fails, it will return false.

PHP version

This function will return a resource identifier if there is no error. If the key generation fails, it will return false.5Starting from PHP version .0.0.

Example1

The work of openssl_pkey_new():

Example

<?php
　　　//Generate a new private key (and public key) pair
　　　$privkey = openssl_pkey_new(array(
　　　　　　"digest_alg" => md5',
　　　　　　"private_key_bits" =>　2048,
　　　　　　"private_key_type" => OPENSSL_KEYTYPE_RSA,
　　　));
	var_dump($privkey);
?>

This will produce the following results:

resource(2) of type (OpenSSL key)

Example2

The work of openssl_pkey_new() and openssl_pkey_get_details:

Example

<?php
　　　//Generate a new private key (and public key) pair
　　　$privkey = openssl_pkey_new(array(
　　　　　　"digest_alg" => md5',
　　　　　　"private_key_bits" =>　2048,
　　　　　　"private_key_type" => OPENSSL_KEYTYPE_RSA,
　　　));
　　　$key_details = openssl_pkey_get_details($privkey);
　　　print_r($key_details);
?>

This will produce the following results:

Array
(
　　　　[bits] =>　2048
　　　　[key] =>　-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA1IGWxnWzICSkjrOVrYkw
9EKpIhcAYbhaymiwQY/ii9d7hnuGhpjjitDxzFftGafL6XOFKOhgbO2yrcpFxRKu
AY3t5wyUcqUJV6CNwV2Hipk90psUcTmK3+pcCzcqCKr7sLWlHI48lse92xane8Sf
CATNNbr9vmqUaTZ9FQqWihm3o/rNGuZTwMSKvcKsVguFpwrEDJaSLP1nt7RSHGc+
PixQSXp3PtQCH+S0CM9jt1jD9NkYXuuAlNbrsPm1fl2zAGR5Vh15evz5765lZ2mH
LIZScfsO/qgai3R6foaBlJM5tiSeiVZgnnQDKFBi5XK2GhzDnKggJe4tdY7awTFm
CQIDAQAB
-----END PUBLIC KEY-----
　　　　[rsa] => Array
　　　　　　　　(
　　　　　　　　　　　　[n] => ��u�　$������0�B�"a�Z�h�A���{�{�������W����s�(�`l����E������r�	W���]���=қq9���\7*������<�ǽ��{ğ�5���j�i6}
�������S�Ċ�¬V��
���,�g��Rg>>,PIzw>���c�X���^뀔����~]�dyVyz���egi�,�Rq����tz~����9�$��V`�t(Pb�r�Ü　%�-u���1f	
　　　　　　　　　　　　[e] =>　
　　　　　　　　　　　　[d] => F"�3����4��!K�yF��R�lY�9�]Ξ��A��@�f��~�<�YPєG��=���TkTP�rl�Mԓ{�lŮ^��!����q�˂�7�|�f����lE+#�@�.�GIH�tS�R.mbc�U~����7&w�ݥ�P.Fe�ϨU�@��m��X�ECsemjI$@/�$l����)�8�@���c�w�NRo���+!'�.����fvT7�=n")LQ�sd�%zZ���G��{�{�1A^�v��E
　　　　　　　　　　　　[p] => =>u)�1The current K�r���pHE��k���LBE����y�'�3-�/��Pd���jeFV1����?�.O�����:�bl2�z�U�{��{��*��A���<�}m4��J�Y�'���f@�����
　　　　　　　　　　　　[q] => ߦz\��96�=��V]"k��2w���>�r�袤�6�/�-Z�_�����8!Y��I��L���_3Ym�����.p�֏^����>�I:��oZ��"���=��8���뻢1�����:�
　　　　　　　　　　　　[dmp1] => z"�TW*��Ƴm�$�HQ�$0���sa��j� #
P�*�P��Q�G\42�a�26(�5�K�7zj���xj7��@e�$.6��b�Dq]]I}�L�m�d��54)@:���#
　　　　　　　　　　　　[dmq1] =>　+����4}��\dc�R�K�Bw�\�E6�ؓ�����%_�m$3蚞9��Fh�D�uz����$�8HPK�ˇԁ^���K�k�]e�g�>ºX�"<ƌ���`ė���&9E��MS"��¥�)
　　　　　　　　　　　　[iqmp] => !�����߷�=�z�=ܰ7����V�6q�~���3V��t�P�$��O�kgv��3=W\ѝm���	�J���5^�K��a�t��~������U�.��!�l�v�#��z*�	���r
　　　　　　　　)
　　　　[type] => 0
)

Example3

To read the public key from openssl_pkey_new():

Example

<?php
　　　echo 'The hash of Welcome to w3codebox is　-　.hash('crc32b', 'Welcome to w3codebox');
?>

This will produce the following results:

Example4

To store the public key in the file from openssl_pkey_new():

Example

<?php
　　　//　Generate a new private key (and public key) pair
　　　$privkey = openssl_pkey_new(array(
　　　　　　"digest_alg" => md5',
　　　　　　"private_key_bits" =>　2048,
　　　　　　"private_key_type" => OPENSSL_KEYTYPE_RSA,
　　　));
　　　$keydetails = openssl_pkey_get_details($privkey);
　　　//To save the public key to a file
　　　file_put_contents('mypublic.key', $keydetails['key']);
?>

The content of the file mypublic.key is:

PHP OpenSSL Function Manual

PHP CURL Functions PHP OpenSSL Functions