(Node.js) JWE using "dir" Direct use of Shared Symmetric Key

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

Note: This example requires Chilkat v9.5.0.66 or greater.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // 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.

    var success;
    var plaintext = "Live long and prosper.";

    var jwe = new chilkat.Jwe();

    // First build the JWE Protected Header..
    var jweProtHdr = new chilkat.JsonObject();
    jweProtHdr.AppendString("alg","dir");
    jweProtHdr.AppendString("enc","A128GCM");

    // Don't forget to actually provide the protected header to the JWE object:
    jwe.SetProtectedHeader(jweProtHdr);

    // The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
    // Given that the "alg" = "dir", we are to directly specify the AES GCM key.
    // (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

    // Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

    // The SetWrappingKey method is also used for "dir" direct keys.
    // However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
    // which is specified by calling SetWrappingKey with an index of 0.

    var recipientIndex = 0;
    jwe.SetWrappingKey(recipientIndex,"000102030405060708090A0B0C0D0E0F","hex");

    // Encrypt and return the JWE:
    var strJwe = jwe.Encrypt(plaintext,"utf-8");
    if (jwe.LastMethodSuccess !== true) {
        console.log(jwe.LastErrorText);
        return;
    }

    // Show the JWE we just created:
    console.log(strJwe);

    // Decrypt the JWE.
    var jwe2 = new chilkat.Jwe();
    success = jwe2.LoadJwe(strJwe);
    if (success !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

    jwe2.SetWrappingKey(0,"000102030405060708090A0B0C0D0E0F","hex");

    // Decrypt.
    var originalPlaintext = jwe2.Decrypt(0,"utf-8");
    if (jwe2.LastMethodSuccess !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

    console.log("original text: ");
    console.log(originalPlaintext);

    // Sample output:
    // eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
    // original text: 
    // Live long and prosper.

}

chilkatExample();