(PHP ActiveX) RSA Encrypt and Decrypt Strings

PHP ActiveX sample code to RSA public-key encrypt and decrypt strings using public and private keys.

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

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Rsa')
$rsa = new COM("Chilkat.Rsa");

// This example also generates the public and private
// keys to be used in the RSA encryption.
// Normally, you would generate a key pair once,
// and distribute the public key to your partner.
// Anything encrypted with the public key can be
// decrypted with the private key.  The reverse is 
// also true: anything encrypted using the private
// key can be decrypted using the public key.

// Generate a 1024-bit key.  Chilkat RSA supports
// key sizes ranging from 512 bits to 4096 bits.
$success = $rsa->GenerateKey(1024);
if ($success != 1) {
    print $rsa->LastErrorText . "\n";
    exit;
}

// Keys are exported in XML format:
$publicKey = $rsa->exportPublicKey();
$privateKey = $rsa->exportPrivateKey();

$plainText = 'Encrypting and decrypting should be easy!';

// Start with a new RSA object to demonstrate that all we
// need are the keys previously exported:
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Rsa')
$rsaEncryptor = new COM("Chilkat.Rsa");

// Encrypted output is always binary.  In this case, we want
// to encode the encrypted bytes in a printable string.
// Our choices are "hex", "base64", "url", "quoted-printable".
$rsaEncryptor->EncodingMode = 'hex';

// We'll encrypt with the public key and decrypt with the private
// key.  It's also possible to do the reverse.
$success = $rsaEncryptor->ImportPublicKey($publicKey);

$usePrivateKey = 0;
$encryptedStr = $rsaEncryptor->encryptStringENC($plainText,$usePrivateKey);
print $encryptedStr . "\n";

// Now decrypt:
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Rsa')
$rsaDecryptor = new COM("Chilkat.Rsa");

$rsaDecryptor->EncodingMode = 'hex';
$success = $rsaDecryptor->ImportPrivateKey($privateKey);

$usePrivateKey = 1;
$decryptedStr = $rsaDecryptor->decryptStringENC($encryptedStr,$usePrivateKey);

print $decryptedStr . "\n";

?>