Create Private and Public Keys using PHP

pub_priv_keys.php

<?php

$config = array(
  "digest_alg" => "sha512",
  "private_key_bits" => 4096,
  "private_key_type" => OPENSSL_KEYTYPE_RSA,
);
    
// Create the private and public key
$result = openssl_pkey_new( $config );

// Extract the private key from $result to $privKey
openssl_pkey_export( $result, $privKey );

// Extract the public key from $result to $pubKey
$pubKey = openssl_pkey_get_details( $result );
$pubKey = $pubKey["key"];

// save private key to file
file_put_contents( 'private.key', $privKey );

// save public key to file
file_put_contents( 'public.pub', $pubKey );