(Node.js) JWE with DEFLATE Compression

Demonstrates how to DEFLATE ("zip") compress the JWE payload prior to encryption.

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;
    // Create some plaintext to be encrypted.
    // This example will demonstrate with and without DEFLATE (zip) compression.
    var sbPlainText = new chilkat.StringBuilder();
    var bCrLf = true;
    var line = "Live long and prosper.";
    sbPlainText.AppendLine(line,bCrLf);
    sbPlainText.AppendLine(line,bCrLf);
    sbPlainText.AppendLine(line,bCrLf);
    sbPlainText.AppendLine(line,bCrLf);

    // The text to be encrypted:
    console.log(sbPlainText.GetAsString());

    var jwe = new chilkat.Jwe();

    // Build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256","zip":"DEF"}
    // The "zip":"DEF" parameter indicates that the plaintext payload should
    // be compressed prior to encryption.
    var jweProtHdr = new chilkat.JsonObject();
    jweProtHdr.AppendString("alg","A128KW");
    jweProtHdr.AppendString("enc","A128CBC-HS256");
    jweProtHdr.AppendString("zip","DEF");
    jwe.SetProtectedHeader(jweProtHdr);

    // Set the AES key wrap key:
    var aesWrappingKey = "GawgguFyGrWKav7AX4VKUg";
    jwe.SetWrappingKey(0,aesWrappingKey,"base64url");

    // Encrypt and return the JWE in sbJweCompressed:
    var sbJweCompressed = new chilkat.StringBuilder();
    success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweCompressed);
    if (success !== true) {
        console.log(jwe.LastErrorText);
        return;
    }

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

    // Now create a JWE without compression.
    jweProtHdr.Delete("zip");
    // Make sure to update the shared protected header:
    jwe.SetProtectedHeader(jweProtHdr);

    var sbJweUncompressed = new chilkat.StringBuilder();
    success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweUncompressed);
    if (success !== true) {
        console.log(jwe.LastErrorText);
        return;
    }

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

    // Decrypting is the same whether compression is used or not.
    // The "zip" header in the JWE indicates that the payload should be 
    // automatically decompressed (inflated) after decrypting.
    var jwe2 = new chilkat.Jwe();
    success = jwe2.LoadJweSb(sbJweCompressed);
    if (success !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

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

    // Decrypt (also automatically decompresses).
    var sbOriginalText = new chilkat.StringBuilder();
    success = jwe2.DecryptSb(0,"utf-8",sbOriginalText);
    if (success !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

    console.log("original text from compressed JWE: ");
    console.log(sbOriginalText.GetAsString());

    // -----------------------------------------------------------
    // Do the same with the uncompressed JWE

    success = jwe2.LoadJweSb(sbJweUncompressed);
    if (success !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

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

    // Decrypt.
    sbOriginalText.Clear();
    success = jwe2.DecryptSb(0,"utf-8",sbOriginalText);
    if (success !== true) {
        console.log(jwe2.LastErrorText);
        return;
    }

    console.log("original text from uncompressed JWE: ");
    console.log(sbOriginalText.GetAsString());

    // ------------------------------------------------
    // The output of this example is:
    // (Note: Your output data will be different because the content encryption key is randomly generated.)

    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiemlwIjoiREVGIn0.xuW-pEAIdEUFnk10m8ocursvktO8Of9ByCCAt6LgKkkOtCWCUn1kQw.zpGj-9WVni3cQxyOuZbcGA.0hzP1myua3oYpUHwCIY_3edBUREbUpLaX6wYuJduOdI.Ppc6aEO3y3B8BJ1FKMPjlA
    // size of compressed JWE: 212
    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.N4KeyC7nnSFkieJOyE24_zKeuV_m7v5UKoJb1TgV4Yc_r2RzUPNvyA.6AEdyXSCKx-iMmUJyypSLg.QpixfyrwhGpmwUDp623viik4smPav7vwPLiC2r-V-jwnSfEH3mxWu6DbrIz3mixaqATwynmEBzVPxvS9jTXpSAGCnniib4_0WoPl3r_wF5tlsKOEe--jpNso-DKd1Tp8jJxj3JkFWt3IRnUUKGj17g.sBfDwFc5fzpaI-UW8-SW4g
    // size of uncompressed JWE: 303
    // original text from compressed JWE: 
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // 
    // original text from uncompressed JWE: 
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // 

}

chilkatExample();