php openssl pkcs8

PHP OpenSSL PKCS8 is a function in PHP that generates a PKCS#8 compatible private key from an existing OpenSSL (PEM) formatted private key. PKCS#8 is a standard that defines the syntax for private key information.

The function is called openssl_pkcs8() and takes four parameters:

- $private_key: The OpenSSL (PEM) formatted private key.
- $output: A variable to store the generated PKCS#8 private key.
- $passphrase: An optional passphrase to encrypt the PKCS#8 private key.
- $options: An optional array of options that can be used to modify the behavior of the function.

Here is an example usage of openssl_pkcs8():

<?php
// Generate a PKCS#8 private key from an existing OpenSSL (PEM) formatted private key.
$private_key = "-----BEGIN PRIVATE KEY-----
MIIEvAIBADANBgkqhkiG9w0BAQEFAASCBKYwggSiAgEAAoIBAQCYOZvNfIjS1yN7
...
-----END PRIVATE KEY-----";

// Generate the PKCS#8 private key.
openssl_pkcs8($private_key, $output, null, []);

// Output the generated PKCS#8 private key.
echo $output;
?>

Note that the generated PKCS#8 private key will be in binary format. To convert it to a PEM format, you can use the openssl_pkey_export() function.