(Node.js) Create JWS using the Flattened JSON Serialization Format

Creates a JSON Web Signature (JWS) containing 1 signature and output using the flattened JSON serialization format.

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, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

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.

    // The JWS to be created will contain one signature using an ECDSA key.

    var sbEccJwk = new chilkat.StringBuilder();
    sbEccJwk.Append("{\"kty\":\"EC\",");
    sbEccJwk.Append("\"crv\":\"P-256\",");
    sbEccJwk.Append("\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",");
    sbEccJwk.Append("\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\",");
    sbEccJwk.Append("\"d\":\"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI\"");
    sbEccJwk.Append("}");

    var eccKey = new chilkat.PrivateKey();
    // Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
    // into the private key object. (See the online reference documentation..)
    var success = eccKey.LoadJwk(sbEccJwk.GetAsString());
    if (success !== true) {
        console.log(eccKey.LastErrorText);
        return;
    }

    // ---------------------------------------------------
    // Prepare both a protected and unprotected header.

    var jwsProtHdr = new chilkat.JsonObject();
    jwsProtHdr.AppendString("alg","ES256");

    var jwsUnprotHdr = new chilkat.JsonObject();
    jwsUnprotHdr.AppendString("kid","myEcKey");

    // ---------------------------------------------------
    var jws = new chilkat.Jws();

    jws.SetProtectedHeader(0,jwsProtHdr);
    jws.SetUnprotectedHeader(0,jwsUnprotHdr);

    jws.SetPrivateKey(0,eccKey);

    var bIncludeBom = false;
    var payloadStr = "In our village, folks say God crumbles up the old moon into stars.";
    jws.SetPayload(payloadStr,"utf-8",bIncludeBom);

    // ---------------------------------------------------
    // Create the JWS.
    // Indicate we prefer the non-compact, flattened serialization.
    jws.PreferCompact = false;
    jws.PreferFlattened = true;

    var jwsStr = jws.CreateJws();
    if (jws.LastMethodSuccess !== true) {
        console.log(jws.LastErrorText);
        return;
    }

    // The jwsStr is contains the flattened JSON in the smallest possible size, which is a single line.
    // To get in human-readable format, load into a Chilkat JSON object and emit..
    var json = new chilkat.JsonObject();
    json.Load(jwsStr);
    json.EmitCompact = false;
    console.log(json.Emit());

    // Sample output:

    // { 
    //   "payload": "SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu",
    //   "protected": "eyJhbGciOiJFUzI1NiJ9",
    //   "header": { 
    //     "kid": "myEcKey"
    //   },
    //   "signature": "b7V2UpDPytr-kMnM_YjiQ3E0J2ucOI9LYA7mt57vccrK1rb84j9areqgQcJwOA00aWGoz4hf6sMTBfobdcJEGg"
    // }

}

chilkatExample();