Node.js

JWE with Binary Data

See more JSON Web Encryption (JWE) Examples

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.

Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    // 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.

    // 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();