(Node.js) JWE with Binary Data

Demonstrates how to create a JWE that contains a binary payload (such as a JPG image).

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;

    // Load a JPG file that will be the JWE payload.
    var jpgBytes = new chilkat.BinData();
    success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg");
    // Make sure your app checks the success/failure of the call to LoadFile..
    console.log("Original JPG size = " + jpgBytes.NumBytes);

    var jwe = new chilkat.Jwe();

    var jweProtHdr = new chilkat.JsonObject();
    jweProtHdr.AppendString("alg","A128KW");
    jweProtHdr.AppendString("enc","A128CBC-HS256");
    jwe.SetProtectedHeader(jweProtHdr);

    var aesWrappingKey = "GawgguFyGrWKav7AX4VKUg";
    jwe.SetWrappingKey(0,aesWrappingKey,"base64url");

    // Encrypt and return the JWE in sbJwe:
    var sbJwe = new chilkat.StringBuilder();
    success = jwe.EncryptBd(jpgBytes,sbJwe);
    if (success !== true) {
        console.log(jwe.LastErrorText);
        return;
    }

    // Show the JWE:
    console.log(sbJwe.GetAsString());
    console.log("size of JWE: " + sbJwe.Length);

    // ---------------------------------------------------------
    // Decrypt to get the original JPG file..

    var jwe2 = new chilkat.Jwe();
    success = jwe2.LoadJweSb(sbJwe);
    if (success !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

    // Set the AES wrap key.
    jwe2.SetWrappingKey(0,aesWrappingKey,"base64url");

    // Decrypt.
    var jpgOriginal = new chilkat.BinData();
    success = jwe2.DecryptBd(0,jpgOriginal);
    if (success !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

    console.log("Decrypted JPG size = " + jpgOriginal.NumBytes);

    // Save the decrypted JPG to a file.
    success = jpgOriginal.WriteFile("qa_output/jwe_decrypted_starfish.jpg");

    console.log("success = " + success);

    // The output of this program, when tested, was:
    // Original JPG size = 6229
    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.9YFz_wteV ... 7Et3hKhpxnKEXw
    // size of JWE: 8473
    // Decrypted JPG size = 6229
    // success = True

}

chilkatExample();