(PHP Extension) Validate JWS Using RSASSA-PKCS1-v1_5 SHA-256

Validates a JSON Web Signature (JWS) that uses RSASSA-PKCS1-v1_5 SHA-256.

Note: This example requires Chilkat v9.5.0.66 or greater.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

// Note: This example requires Chilkat v9.5.0.66 or greater.

// This example takes a JSON signature in compact serialization format,
// and uses an RSA public key to validate and recover the protected header and payload.

// We only need a public key for signature validation.  This is the RSA public key
// that is used:

//      {"kty":"RSA", 
//       "n":"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx
//            HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs
//            D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH
//            SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV
//            MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8
//            NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ", 
//       "e":"AQAB"
//      }

$sbPubKey = new CkStringBuilder();
$sbPubKey->Append('{\'kty\':\'RSA\',');
$sbPubKey->Append('\'n\':\'ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx');
$sbPubKey->Append('HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs');
$sbPubKey->Append('D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH');
$sbPubKey->Append('SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV');
$sbPubKey->Append('MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8');
$sbPubKey->Append('NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ\',');
$sbPubKey->Append('\'e\':\'AQAB\'');
$sbPubKey->Append('}');

$pubKey = new CkPublicKey();
$success = $pubKey->LoadFromString($sbPubKey->getAsString());
if ($success != true) {
    print $pubKey->lastErrorText() . "\n";
    exit;
}

$jws = new CkJws();

// Set the RSA public key:
$signatureIndex = 0;
$jws->SetPublicKey($signatureIndex,$pubKey);

// Load the JWS.
$sbJws = new CkStringBuilder();
$sbJws->Append('eyJhbGciOiJSUzI1NiJ9');
$sbJws->Append('.');
$sbJws->Append('eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt');
$sbJws->Append('cGxlLmNvbS9pc19yb290Ijp0cnVlfQ');
$sbJws->Append('.');
$sbJws->Append('cC4hiUPoj9Eetdgtv3hF80EGrhuB__dzERat0XF9g2VtQgr9PJbu3XOiZj5RZmh7');
$sbJws->Append('AAuHIm4Bh-0Qc_lF5YKt_O8W2Fp5jujGbds9uJdbF9CUAr7t1dnZcAcQjbKBYNX4');
$sbJws->Append('BAynRFdiuB--f_nZLgrnbyTyWzO75vRK5h6xBArLIARNPvkSjtQBMHlb1L07Qe7K');
$sbJws->Append('0GarZRmB_eSN9383LcOLn6_dO--xi12jzDwusC-eOkHWEsqtFZESc6BfI7noOPqv');
$sbJws->Append('hJ1phCnvWh6IeYI2w9QOYEUipUTI8np6LbgGY9Fs98rqVt5AXLIhWkWywlVmtVrB');
$sbJws->Append('p0igcN_IoypGlUPQGe77Rw');

$success = $jws->LoadJwsSb($sbJws);
if ($success != true) {
    print $jws->lastErrorText() . "\n";
    exit;
}

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

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

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

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

// Examine the protected header:
// joseHeader is a CkJsonObject
$joseHeader = $jws->GetProtectedHeader($signatureIndex);
if ($jws->get_LastMethodSuccess() != true) {
    print 'No protected header found at the given index.' . "\n";
    exit;
}

$joseHeader->put_EmitCompact(false);

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

// Output:

// 	Signature validated.
// 	--
// 	Recovered content:
// 	{"iss":"joe", 
// 	 "exp":1300819380,
// 	 "http://example.com/is_root":true}
// 	--
// 	Protected (JOSE) header:
// 	{ 
// 	  "alg": "RS256"
// 	}

?>