PHP Extension

RSA Encrypt String to Encoded Result and Reverse

See more RSA Examples

Demonstrates how to RSA encrypt a string to a base64 encoded result, and the reverse. PHP Extension

<?php

include("chilkat.php");

$success = false;

// The RSA public key is used for encryption, and the private key for decryption.

// The public key's role is to make encryption accessible to anyone while ensuring that
// only the private key holder can decrypt the messages.
// The public key is designed to be widely distributed so anyone can use it to encrypt messages
// intended for the owner of the private key.

$glob = new CkGlobal();
$glob->put_DefaultUtf8(true);

// Load our 2048-bit RSA public key.
$pubKey = new CkPublicKey();
// In all Chilkat methods expecting a path, you pass either absolute or relative paths.
$success = $pubKey->LoadFromFile('rsaKeys/myTestRsaPublic.pem');
if ($success == false) {
    print $pubKey->lastErrorText() . "\n";
    exit;
}

$rsa = new CkRsa();

// Tell RSA to use the public key.
$rsa->UsePublicKey($pubKey);

// RSA encryption is for small amounts of data, on the order of 200 bytes or less.
// The maximum number of bytes that can be RSA encrypted depends
// on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
// For specific limits, see: RSA Encryption Maximum Number of Bytes

// Encrypt the utf-8 byte representation of the string.
$rsa->put_Charset('utf-8');
$rsa->put_EncodingMode('base64');

// Be Careful when Using non-us-ascii String Literals in Source Code
$encryptedB64 = $rsa->encryptStringENC('Élève français dîne à côté d’un café où l’on sert déjà du gâteau au chocolat et des éclairs délicieux',false);

// ------------------------------------------------------------------------------------------------------------------------
// Let's decrypt, which requires the matching private key...

// Load the matching 2048-bit RSA private key.
$privKey = new CkPrivateKey();
$password = 'secret';
$success = $privKey->LoadAnyFormatFile('rsaKeys/myTestRsaPrivate.pem',$password);
if ($success == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

// Tell the RSA object to use the private key.
$rsa->UsePrivateKey($privKey);

// Indicate that after decrypting the resultant decrypted bytes contains the utf-8 byte representation of the text.
$rsa->put_Charset('utf-8');
$rsa->put_EncodingMode('base64');
$originalText = $rsa->decryptStringENC($encryptedB64,true);
if ($success == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

print 'Original text = ' . $originalText . "\n";
print 'Success.' . "\n";

?>