How to create a new key pair and save them in files?

Question

How to create a new key pair and save them in files? OpenSSL, I think. I have Windows 7 and Xampp that have OpenSSL in the APache directory (although I am having some problems with openssl_pkey_new () (see Why does openssl_pkey_new () fail? ).

Anyway, as soon as I tune in to OpenSSL, what does the code look like to create a new key pair and save them in files?

Answer 1

To create a key pair:

<?php
/* Create the private and public key */
$res = openssl_pkey_new();

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

/* Extract the public key from $res to $pubKey */
$pubKey = openssl_pkey_get_details($res);
$pubKey = $pubKey["key"];
?>

To save the key in the target file:

file_put_contents($file, $key);