(PHP Extension) Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Note: This example requires Chilkat v11.5.0 or greater.

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<?php

include("chilkat.php");

$success = false;

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

// Load the certificate from a smart card.
$cert = new CkCert();

// Set the smarcard PIN prior to loading.
$cert->put_SmartCardPin('123456');

// Detect the connected smartcard or USB security token and load the default certificate.
$success = $cert->LoadFromSmartcard('');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

// Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
// such as selecting a certificate if the card contains multiple certificates with private keys,
// or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

// Create the JWS Protected Header
$jwsProtHdr = new CkJsonObject();

if ($cert->IsEcdsa() == true) {
    $jwsProtHdr->AppendString('alg','ES256');
}
else {
    $jwsProtHdr->AppendString('alg','RS256');
}

$jws = new CkJws();

// Set the protected header:
$signatureIndex = 0;
$jws->SetProtectedHeader($signatureIndex,$jwsProtHdr);

// Provide the private key via the certificate.
// This requires Chilkat v11.5.0 or greater.
$jws->SetSigningCert($signatureIndex,$cert);

// Set the payload.
$bIncludeBom = false;
$payloadStr = 'In our village, folks say God crumbles up the old moon into stars.';
$jws->SetPayload($payloadStr,'utf-8',$bIncludeBom);

// Create the JWS
// By default, the compact serialization is used.
$jwsCompact = $jws->createJws();
if ($jws->get_LastMethodSuccess() == false) {
    print $jws->lastErrorText() . "\n";
    exit;
}

print 'JWS: ' . $jwsCompact . "\n";

// sample output:
// JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

// Now load the JWS, validate, and recover the original text.
$jws2 = new CkJws();

// Load the JWS.
$success = $jws2->LoadJws($jwsCompact);

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

// Set the public key used for validation.
$signatureIndex = 0;
$jws2->SetPublicKey($signatureIndex,$pubKey);

// Validate the 1st (and only) signature at index 0..
$v = $jws2->Validate($signatureIndex);
if ($v < 0) {
    // Perhaps Chilkat was not unlocked or the trial expired..
    print 'Method call failed for some other reason.' . "\n";
    print $jws2->lastErrorText() . "\n";
    exit;
}

if ($v == 0) {
    print 'Invalid signature.  The key was incorrect, the JWS was invalid, or both.' . "\n";
    exit;
}

// If we get here, the signature was validated..
print 'Signature validated.' . "\n";

// Recover the original content:
print $jws2->getPayload('utf-8') . "\n";

// Examine the protected header:

$joseHeader = new CkJsonObject();
$success = $jws2->GetProtectedH($signatureIndex,$joseHeader);
if ($success == false) {
    print $jws2->lastErrorText() . "\n";
    exit;
}

$joseHeader->put_EmitCompact(false);

print 'Protected (JOSE) header:' . "\n";
print $joseHeader->emit() . "\n";

// Output:

// 	Signature validated.
// 	In our village, folks say God crumbles up the old moon into stars.
// 	Protected (JOSE) header:
// 	{ 
// 	  "alg": "RS256"
// 	}

?>