Perl Requires Chilkat v11.0.0+

Validate a JWS Using ECDSA P-256 SHA-256

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) that uses ECDSA P-256 SHA-256 Perl

use chilkat();

$success = 0;

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

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

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

#       {"kty":"EC", 
#        "crv":"P-256", 
#        "x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU", 
#        "y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0" 
#       } 

$sbPubKey = chilkat::CkStringBuilder->new();
$sbPubKey->Append("{\"kty\":\"EC\",");
$sbPubKey->Append("\"crv\":\"P-256\",");
$sbPubKey->Append("\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",");
$sbPubKey->Append("\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\"");
$sbPubKey->Append("}");

$pubKey = chilkat::CkPublicKey->new();
$success = $pubKey->LoadFromString($sbPubKey->getAsString());
if ($success == 0) {
    print $pubKey->lastErrorText() . "\r\n";
    exit;
}

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

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

#  Load the JWS.
$sbJws = chilkat::CkStringBuilder->new();
$sbJws->Append("eyJhbGciOiJFUzI1NiJ9");
$sbJws->Append(".");
$sbJws->Append("eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt");
$sbJws->Append("cGxlLmNvbS9pc19yb290Ijp0cnVlfQ");
$sbJws->Append(".");
$sbJws->Append("DtEhU3ljbEg8L38VWAfUAqOyKAM6-Xx-F4GawxaepmXFCgfTjDxw5djxLa8ISlSA");
$sbJws->Append("pmWQxfKTUJqPP3-Kg6NU1Q");

$success = $jws->LoadJwsSb($sbJws);
if ($success == 0) {
    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 ECC 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 = chilkat::CkJsonObject->new();
$success = $jws->GetProtectedH($signatureIndex,$joseHeader);
if ($success == 0) {
    print $jws->lastErrorText() . "\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": "ES256"
#  	}