PHP Extension

Export a Private Key as DER into a BinData

Demonstrates the Chilkat PrivateKey.GetPkcsBd method, which exports the key as DER into a BinData. The first argument selects PKCS #1 (true) versus PKCS #8 (false), the second is the password (empty for unencrypted), and the third is the BinData that receives the bytes.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is the in-memory binary export — the raw DER bytes land in a BinData ready to hash, encrypt, or hand to another API without a temporary file. One method covers several cases: the boolean picks the traditional (PKCS #1) versus modern (PKCS #8) structure, and a nonempty password produces an encrypted PKCS #8 export (with the cipher from Pkcs8EncryptAlg). Source any password securely.

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<?php

include("chilkat.php");

$success = false;

//  Load a private key to export.
$privKey = new CkPrivateKey();
$success = $privKey->LoadPemFile('qa_data/private.pem');
if ($success == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

//  The key password is not hard-coded in a real application; obtain it from an interactive
//  prompt, environment variable, or a secrets vault.
$password = 'myKeyPassword';

//  Export the key as DER into a BinData.  The 1st argument selects PKCS #1 (true) versus PKCS #8
//  (false); the 2nd is the password (empty string for an unencrypted export); the 3rd is the
//  BinData that receives the DER bytes.
$usePkcs1 = false;
$bd = new CkBinData();
$success = $privKey->GetPkcsBd($usePkcs1,$password,$bd);
if ($success == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

print 'Exported ' . $bd->get_NumBytes() . ' DER bytes.' . "\n";

?>