(Perl) JWE using PBES2 Key Wrapping

Demonstrates how to create and decrypt a JWE that using PBES2 key wrapping.

This example demonstrates PBES2 with HMAC SHA-256 and A128KW wrapping. It is also possible to do the following by simply changing the "alg" parameter:

• PBES2 with HMAC SHA-384 and A192KW wrapping
• PBES2 with HMAC SHA-512 and A256KW wrapping

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..
$jweProtHdr = chilkat::CkJsonObject->new();
$jweProtHdr->AppendString("alg","PBES2-HS256+A128KW");
$jweProtHdr->AppendString("enc","A128GCM");

# PBES2 requires two additional parameters:
# 1) A random salt parameter ("p2s") containing 8 or more bytes in base64url format.
# 2) An iteration count parameter ("p2c").  A minimum count of 1000 is recommended.
#    The iteration count is intended to make the PBES2 computation more expensive (time consuming)
#    to prevent brute-force attacks.
$prng = chilkat::CkPrng->new();
$jweProtHdr->AppendString("p2s",$prng->genRandom(16,"base64url"));
$jweProtHdr->AppendString("p2c","1000");

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

# Don't forget to actually provide the protected header to the JWE object:
$jwe->SetProtectedHeader($jweProtHdr);

# Set the PBES2 password
$recipientIndex = 0;
$jwe->SetPassword($recipientIndex,"top secret");

# 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.
$jwe2 = chilkat::CkJwe->new();
$success = $jwe2->LoadJwe($strJwe);
if ($success != 1) {
    print $jwe2->lastErrorText() . "\r\n";
    exit;
}

# Set the PBES2 password
$jwe2->SetPassword($recipientIndex,"top secret");

# 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";

# Sample output:

# JWE Protected Header: {"alg":"PBES2-HS256+A128KW","enc":"A128GCM","p2s":"z39rTEfRy1T1Yn_D1mZRlg","p2c":"1000"}
# --
# eyJhbGciOiJQQkVTMi1IUzI1NitBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIiwicDJzIjoiejM5clRFZlJ5MVQxWW5fRDFtWlJsZyIsInAyYyI6IjEwMDAifQ.koYt6PrFmYwcwdcT7ZcvXHA1d-Xez5h4.luGlbvEnZp-7IsBOj42Yhw.YMTcfLf8Qe4zazozGV2OAu3cUdQ8Kg.rWub47ESWkc6IqZJTvSTmg
# original text: 
# Live long and prosper.