(Perl) 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.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

# 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 = chilkat::CkStringBuilder->new();
$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 = chilkat::CkPublicKey->new();
$success = $pubKey->LoadFromString($sbPubKey->getAsString());
if ($success != 1) {
    print $pubKey->lastErrorText() . "\r\n";
    exit;
}

$jws = chilkat::CkJws->new();

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

# Load the JWS.
$sbJws = chilkat::CkStringBuilder->new();
$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 != 1) {
    print $jws->lastErrorText() . "\r\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." . "\r\n";
    print $jws->lastErrorText() . "\r\n";
    exit;
}

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

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

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

# Examine the protected header:
# joseHeader is a JsonObject
$joseHeader = $jws->GetProtectedHeader($signatureIndex);
if ($jws->get_LastMethodSuccess() != 1) {
    print "No protected header found at the given index." . "\r\n";
    exit;
}

$joseHeader->put_EmitCompact(0);

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

# Output:

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