PHP Extension

RSA Sign with PKCS8 Encrypted Key

See more RSA Examples

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature (and then verify it). PHP Extension

<?php

include("chilkat.php");

$success = false;

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

$privKey = new CkPrivateKey();

// Load the private key from an RSA PEM file:
$success = $privKey->LoadAnyFormatFile('raul_privateKey.key','a0123456789');
if ($success == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

$rsa = new CkRsa();

// Import the private key into the RSA component:
$success = $rsa->UsePrivateKey($privKey);
if ($success == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

// This example will sign a string, and receive the signature
// in a hex-encoded string.  Therefore, set the encoding mode
// to "hex":
$rsa->put_EncodingMode('hex');

$strData = 'This is the string to be signed.';

// Sign the string using the sha256 hash algorithm.
// Other valid choices are sha1, sha384, sha512 and others.
$hexSig = $rsa->signStringENC($strData,'sha256');
if ($rsa->get_LastMethodSuccess() == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

print $hexSig . "\n";

// Now verify with the public key.
// This example shows how to use the public key from 
// a digital certificate (.cer file)
$cert = new CkCert();
$success = $cert->LoadFromFile('raul_publicKey.cer');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

$pubKey = new CkPublicKey();
$cert->GetPublicKey($pubKey);

$rsa2 = new CkRsa();
$success = $rsa2->UsePublicKey($pubKey);
if ($success == false) {
    print $rsa2->lastErrorText() . "\n";
    exit;
}

// Verify the signature against the original data:
$rsa2->put_EncodingMode('hex');
$success = $rsa2->VerifyStringENC($strData,'sha256',$hexSig);
if ($success == false) {
    print $rsa2->lastErrorText() . "\n";
    exit;
}

print 'Signature verified!' . "\n";

// Verify with incorrect data:
$success = $rsa2->VerifyStringENC('something else','sha256',$hexSig);
if ($success != true) {
    print 'Signature not verified! (which was expected in this case)' . "\n";
}
else {
    print 'Hmmm... that's not right...' . "\n";
}


?>