(Perl) Validate a JWS Using ECDSA P-521 SHA-512

Validates a JSON Web Signature (JWS) that uses ECDSA P-521 SHA-512

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 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-521", 
#       "x":"AekpBQ8ST8a8VcfVOTNl353vSrDCLLJXmPk06wTjxrrjcBpXp5EOnYG_NjFZ6OvLFV1jSfS9tsz4qUxcWceqwQGk", 
#       "y":"ADSmRA43Z1DSNx_RvcLI87cdL07l6jQyyBXMoxVg_l2Th-x3S1WDhjDly79ajL4Kkd0AZMaZmh9ubmf63e3kyMj2" 
#      } 

$sbPubKey = chilkat::CkStringBuilder->new();
$sbPubKey->Append("{\"kty\":\"EC\",");
$sbPubKey->Append("\"crv\":\"P-521\",");
$sbPubKey->Append("\"x\":\"AekpBQ8ST8a8VcfVOTNl353vSrDCLLJXmPk06wTjxrrjcBpXp5EOnYG_NjFZ6OvLFV1jSfS9tsz4qUxcWceqwQGk\",");
$sbPubKey->Append("\"y\":\"ADSmRA43Z1DSNx_RvcLI87cdL07l6jQyyBXMoxVg_l2Th-x3S1WDhjDly79ajL4Kkd0AZMaZmh9ubmf63e3kyMj2\"");
$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 ECC public key:
$signatureIndex = 0;
$jws->SetPublicKey($signatureIndex,$pubKey);

# Load the JWS.
$sbJws = chilkat::CkStringBuilder->new();
$sbJws->Append("eyJhbGciOiJFUzUxMiJ9");
$sbJws->Append(".");
$sbJws->Append("UGF5bG9hZA");
$sbJws->Append(".");
$sbJws->Append("AdwMgeerwtHoh-l192l60hp9wAHZFVJbLfD_UxMi70cwnZOYaRI1bKPWROc-mZZq");
$sbJws->Append("wqT2SI-KGDKB34XO0aw_7XdtAG8GaSwFKdCAPZgoXD2YBJZCPEX3xKpRwcdOO8Kp");
$sbJws->Append("EHwJjyqOgzDO7iKvU8vcnwNrmxYbSW9ERBXukOXolLzeO_Jn");

$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 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 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:
# (the string "Payload" was the content that was signed.)

# 	Signature validated.
# 	--
# 	Recovered content:
# 	Payload
# 	--
# 	Protected (JOSE) header:
# 	{
# 	  "alg": "ES512"
# 	}