PHP ActiveX

Save a Private Key as a Traditional DER File

Demonstrates the Chilkat PrivateKey.SavePkcs1File method, which saves the key using the traditional/preferred unencrypted DER representation. The only argument is the destination path.

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 writes the older, algorithm-specific DER structure — useful for compatibility with tools that predate or do not accept PKCS #8. For new work, PKCS #8 (SavePkcs8File) is more interoperable. The output is unencrypted, so protect the file accordingly.

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<?php

$success = 0;

//  Load a private key to export.
$privKey = new COM("Chilkat.PrivateKey");
$success = $privKey->LoadPemFile('qa_data/private.pem');
if ($success == 0) {
    print $privKey->LastErrorText . "\n";
    exit;
}

//  Save using the traditional/preferred unencrypted DER representation.
$success = $privKey->SavePkcs1File('qa_output/private_pkcs1.der');
if ($success == 0) {
    print $privKey->LastErrorText . "\n";
    exit;
}

print 'Saved.' . "\n";

?>