(Perl) Create a JWS Using ECDSA P-256 SHA-256

Creates and validates a JSON Web Signature (JWS) that uses ECDSA P-256 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.

# Use the following ECC key loaded from JWK format.
$sbJwk = chilkat::CkStringBuilder->new();
$sbJwk->Append("{\"kty\":\"EC\",");
$sbJwk->Append("\"crv\":\"P-256\",");
$sbJwk->Append("\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",");
$sbJwk->Append("\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\",");
$sbJwk->Append("\"d\":\"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI\"");
$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","ES256");

$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: eyJhbGciOiJFUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.J6EGTNkeuEjehHHBu0SOKzifm8r35wbx49A5964pxzB7gannyZZPMkK7vmlaPJ-K8Xmm8cZsQySAPC12Xd8avw

# 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": "ES256"
# }