(Perl) Validate JWS Using HMAC SHA-256

Validates a JSON Web Signature (JWS) using HMAC 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 a MAC key to validate and recover the protected header and payload.

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

# Set the HMAC key:
$hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow";
$signatureIndex = 0;
$jws->SetMacKey($signatureIndex,$hmacKey,"base64url");

# Load the JWS.
$jwsCompact = "eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk";
$success = $jws->LoadJws($jwsCompact);

# 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 MAC 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 "Recovered content:" . "\r\n";
print $jws->getPayload("utf-8") . "\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:
# 	{ 
# 	  "typ": "JWT",
# 	  "alg": "HS256"
# 	}