(Perl) JWE using AES Key Wrap and AES_128_CBC_HMAC_SHA_256

This example duplicates the example A.3 in RFC 7516 for JSON Web Encryption (JWE).

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.

$plaintext = "Live long and prosper.";

$jwe = chilkat::CkJwe->new();

# First build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256"}
$jweProtHdr = chilkat::CkJsonObject->new();
$jweProtHdr->AppendString("alg","A128KW");
$jweProtHdr->AppendString("enc","A128CBC-HS256");
$jwe->SetProtectedHeader($jweProtHdr);

print "JWE Protected Header: " . $jweProtHdr->emit() . "\r\n";
print "--" . "\r\n";

# The example A.3 in RFC 7516 uses the following 128-bit AES key,
# specified in JWK (JSON Web Key) format:
#      {"kty":"oct",
#       "k":"GawgguFyGrWKav7AX4VKUg"
#      }
# This is just a way of saying: The key type ("kty") is 
# a bunch of octets ("k") in base64url encoding.
# We can simply set the AES wrapping key like this:
$aesWrappingKey = "GawgguFyGrWKav7AX4VKUg";
$jwe->SetWrappingKey(0,$aesWrappingKey,"base64url");

# Encrypt and return the JWE:
$strJwe = $jwe->encrypt($plaintext,"utf-8");
if ($jwe->get_LastMethodSuccess() != 1) {
    print $jwe->lastErrorText() . "\r\n";
    exit;
}

# Show the JWE we just created:
print $strJwe . "\r\n";

# Decrypt the JWE that was just produced.
# 1) Load the JWE.
# 2) Set the AES wrapping key.
# 3) Decrypt.
$jwe2 = chilkat::CkJwe->new();
$success = $jwe2->LoadJwe($strJwe);
if ($success != 1) {
    print $jwe2->lastErrorText() . "\r\n";
    exit;
}

# Set the AES wrap key.
$jwe2->SetWrappingKey(0,$aesWrappingKey,"base64url");

# Decrypt.
$originalPlaintext = $jwe2->decrypt(0,"utf-8");
if ($jwe2->get_LastMethodSuccess() != 1) {
    print $jwe2->lastErrorText() . "\r\n";
    exit;
}

print "original text: " . "\r\n";
print $originalPlaintext . "\r\n";

# ---------------------------------------------------------------------------------
# It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.3.7
# because it was produced using the same AES Wrap key.

$sbJwe = chilkat::CkStringBuilder->new();
$sbJwe->Append("eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.");
$sbJwe->Append("6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ.");
$sbJwe->Append("AxY8DCtDaGlsbGljb3RoZQ.");
$sbJwe->Append("KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.");
$sbJwe->Append("U0m_YmjN04DJvceFICbCVQ");

$success = $jwe2->LoadJweSb($sbJwe);
if ($success != 1) {
    print $jwe2->lastErrorText() . "\r\n";
    exit;
}

$jwe2->SetWrappingKey(0,$aesWrappingKey,"base64url");

# Decrypt.
$originalPlaintext = $jwe2->decrypt(0,"utf-8");
if ($jwe2->get_LastMethodSuccess() != 1) {
    print $jwe2->lastErrorText() . "\r\n";
    exit;
}

print $originalPlaintext . "\r\n";