(Perl) Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using the private key associated with a certificate on a smart card.

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.

# Load the certificate from a smart card.
$cert = chilkat::CkCert->new();
$success = $cert->LoadFromSmartcard("");
if ($success == 0) {
    print $cert->lastErrorText() . "\r\n";
    exit;
}

# Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
# such as selecting a certificate if the card contains multiple certificates with private keys,
# or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

# If the associated private key was present on the smartcard, then you can simply
# get it from the Chilkat cert object:
# privKey is a PrivateKey
$privKey = $cert->ExportPrivateKey();
if ($cert->get_LastMethodSuccess() == 0) {
    print $cert->lastErrorText() . "\r\n";
    exit;
}

# You can check the key type to make sure it's RSA.
# This will output "rsa" if the key is RSA.
print "Key type = " . $privKey->keyType() . "\r\n";

# Create the JWS Protected Header
$jwsProtHdr = chilkat::CkJsonObject->new();
$jwsProtHdr->AppendString("alg","RS256");

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

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

# Set the RSA key:
$jws->SetPrivateKey($signatureIndex,$privKey);

# 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";

# sample output:
# JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

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

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

# rsaPubKey is a PublicKey
$rsaPubKey = $privKey->GetPublicKey();

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

# 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 RSA 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": "RS256"
# 	}