(PHP ActiveX) RSA Encrypt/Decrypt Bytes

See more RSA Examples

Demonstrates how to RSA encrypt and decrypt byte data.

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

// 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.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.PublicKey')
$pubKey = new COM("Chilkat.PublicKey");
// In all Chilkat methods expecting a path, you pass either absolute or relative paths.
$success = $pubKey->LoadFromFile('qa_data/rsaKeys/myTestRsaPublic.pem');
if ($success == 0) {
    print $pubKey->LastErrorText . "\n";
    exit;
}

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

// Tell RSA to use the public key.
$rsa->ImportPublicKeyObj($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

// A typical use for RSA is to encrypt symmetric encryption keys, such as an AES key.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Prng')
$prng = new COM("Chilkat.Prng");

$keyBytes = $prng->GenRandomBytes(32);

$encBytes = $rsa->EncryptBytes($keyBytes,0);

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

// Load the matching 2048-bit RSA private key.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.PrivateKey')
$privKey = new COM("Chilkat.PrivateKey");
$password = 'secret';
$success = $privKey->LoadAnyFormatFile('qa_data/rsaKeys/myTestRsaPrivate.pem',$password);
if ($success == 0) {
    print $privKey->LastErrorText . "\n";
    exit;
}

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

$decBytes = $rsa->DecryptBytes($encBytes,1);
if ($success == 0) {
    print $rsa->LastErrorText . "\n";
    exit;
}

print 'Success.' . "\n";

?>