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

Creates and verifies 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.

# Use the following ECC key loaded from JWK format.
$sbJwk = chilkat::CkStringBuilder->new();
$sbJwk->Append("{\"kty\":\"EC\",");
$sbJwk->Append("\"crv\":\"P-521\",");
$sbJwk->Append("\"x\":\"AekpBQ8ST8a8VcfVOTNl353vSrDCLLJXmPk06wTjxrrjcBpXp5EOnYG_NjFZ6OvLFV1jSfS9tsz4qUxcWceqwQGk\",");
$sbJwk->Append("\"y\":\"ADSmRA43Z1DSNx_RvcLI87cdL07l6jQyyBXMoxVg_l2Th-x3S1WDhjDly79ajL4Kkd0AZMaZmh9ubmf63e3kyMj2\",");
$sbJwk->Append("\"d\":\"AY5pb7A0UFiB3RELSD64fTLOSV_jazdF7fLYyuTw8lOfRhWg6Y6rUrPAxerEzgdRhajnu0ferB0d53vM9mE15j2C\"");
$sbJwk->Append("}");

$eccKey = chilkat::CkPrivateKey->new();
# Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
# into the private key object. (See the online reference documentation..)
$success = $eccKey->LoadJwk($sbJwk->getAsString());
if ($success != 1) {
    print $eccKey->lastErrorText() . "\r\n";
    exit;
}

# Create the JWS Protected Header
$jwsProtHdr = chilkat::CkJsonObject->new();
$jwsProtHdr->AppendString("alg","ES512");

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

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

# Set the ECC key:
$jws->SetPrivateKey($signatureIndex,$eccKey);

# Set the payload.
$bIncludeBom = 0;
$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() != 1) {
    print $jws->lastErrorText() . "\r\n";
    exit;
}

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

# Note: ECC signatures use random values, so the output will be different each time a signature is produced.
# sample output:
# JWS: eyJhbGciOiJFUzUxMiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.AFOnOtZ8UTp-ed1PfLfXxwGU7zT_jnmGGxew-d1CP6SfKa5RUhav5mF4szhSof22JaoQ742VIa0eZ0s1rhBnj8y6APr6g6vKzIpYZlJsnjzjUwAjDQOLmcsjxrrRfATh-NEv7G0Z9FrjdJasS44tCG2EnG6aT2TW-sPG0dy5o9jUWCzi

# Now load the JWS, validate, and recover the original text.
$jws2 = chilkat::CkJws->new();

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

# eccPubKey is a PublicKey
$eccPubKey = $eccKey->GetPublicKey();

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

# 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." . "\r\n";
    print $jws2->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";

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

# Examine the protected header:
# joseHeader is a JsonObject
$joseHeader = $jws2->GetProtectedHeader($signatureIndex);
if ($jws2->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.
# 	In our village, folks say God crumbles up the old moon into stars.
# 	Protected (JOSE) header:
# 	{
# 	  "alg": "ES512"
# 	}