(PHP ActiveX) RSA Encrypt Randomly Generated AES Key

Demonstrates how to RSA encrypt a randomly generated AES key.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// First generate a 256-bit AES key (32 bytes).
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Prng')
$prng = new COM("Chilkat.Prng");
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.BinData')
$bdAesKey = new COM("Chilkat.BinData");
$success = $prng->GenRandomBd(32,$bdAesKey);

// Use a public key from a certificate for RSA encryption.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Cert')
$cert = new COM("Chilkat.Cert");

$success = $cert->LoadFromFile('qa_data/pem/mf_public_rsa.pem');
if ($success == 0) {
    print $cert->LastErrorText . "\n";
    exit;
}

// pubKey is a Chilkat.PublicKey
$pubKey = $cert->ExportPublicKey();
if ($cert->LastMethodSuccess != 1) {
    print $cert->LastErrorText . "\n";
    exit;
}

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Rsa')
$rsa = new COM("Chilkat.Rsa");
$success = $rsa->ImportPublicKeyObj($pubKey);
if ($success == 0) {
    print $rsa->LastErrorText . "\n";
    exit;
}

// RSA encrypt our 32-byte AES key.
// The contents of bdAesKey are replaced with result of the RSA encryption.
$success = $rsa->EncryptBd($bdAesKey,0);
if ($success == 0) {
    print $rsa->LastErrorText . "\n";
    exit;
}

// Return the result as a base64 string
$encryptedAesKey = $bdAesKey->getEncoded('base64');

print 'encrypted AES key = ' . $encryptedAesKey . "\n";

?>