PHP Requires Chilkat v11.0.0+

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. Chilkat2 PHP

<?php

use Chilkat2\PrivateKey;
use Chilkat2\PublicKey;
use Chilkat2\Rsa;

$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.

// Load our 2048-bit RSA public key.
$pubKey = new PublicKey();
// In all Chilkat methods expecting a path, you pass either absolute or relative paths.
try {
    $pubKey->LoadFromFile('rsaKeys/myTestRsaPublic.pem');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

$rsa = new Rsa();

// 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->Charset = 'utf-8';
$rsa->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 PrivateKey();
$password = 'secret';
try {
    $privKey->LoadAnyFormatFile('rsaKeys/myTestRsaPrivate.pem', $password);
    $success = true;
} catch (\Chilkat2\Exception $e) {
    $success = false;
}
if (!$success) {
    echo $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->Charset = 'utf-8';
$rsa->EncodingMode = 'base64';
$originalText = $rsa->DecryptStringENC($encryptedB64, true);
if (!$success) {
    echo $rsa->LastErrorText, "\n";
    exit;
}

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