(PHP Extension) RSA Sign Binary Data and Verify (Recover the Original Data)

Demonstrates how to RSA sign binary data and then verify/recover the original data.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

Note: This example requires Chilkat v11.0.0 or greater.

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<?php

include("chilkat.php");

$success = false;

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

// Load an RSA private key for signing.
$privKey = new CkPrivateKey();
$success = $privKey->LoadEncryptedPemFile('qa_data/pem/rsa_passwd.pem','passwd');
if ($success == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

$rsa = new CkRsa();
$rsa->UsePrivateKey($privKey);

// We have some binary data (in hex) to sign
$originalData = '0102030405060708090A';
$bd = new CkBinData();
$bd->AppendEncoded($originalData,'hex');

// If successful, the contents of bd are replaced with the RSA signature.
$success = $rsa->SignRawBd($bd);
if ($success == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

// Show the RSA signature in base64
print $bd->getEncoded('base64') . "\n";

// ------------------------------------------
// Get the public key from the private key
$pubKey = new CkPublicKey();
$privKey->ToPublicKey($pubKey);

// Verify the signature and extract the original data.
$rsa2 = new CkRsa();
$rsa2->UsePublicKey($pubKey);

$bVerified = $rsa2->VerifyRawBd($bd);
print 'signature verified: ' . $bVerified . "\n";

// Show the original data:
print 'original data: ' . $bd->getEncoded('hex') . "\n";

?>