Node.js

Create a JWS Using ECDSA P-256 SHA-256

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) that uses ECDSA P-256 SHA-256 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.

    // Use the following ECC key loaded from JWK format.
    var sbJwk = new chilkat.StringBuilder();
    sbJwk.Append("{\"kty\":\"EC\",");
    sbJwk.Append("\"crv\":\"P-256\",");
    sbJwk.Append("\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",");
    sbJwk.Append("\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\",");
    sbJwk.Append("\"d\":\"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI\"");
    sbJwk.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..)
    success = eccKey.LoadJwk(sbJwk.GetAsString());
    if (success == false) {
        console.log(eccKey.LastErrorText);
        return;
    }

    // Create the JWS Protected Header
    var jwsProtHdr = new chilkat.JsonObject();
    jwsProtHdr.AppendString("alg","ES256");

    var jws = new chilkat.Jws();

    // Set the protected header:
    var signatureIndex = 0;
    jws.SetProtectedHeader(signatureIndex,jwsProtHdr);

    // Set the ECC key:
    jws.SetPrivateKey(signatureIndex,eccKey);

    // Set the payload.
    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
    // By default, the compact serialization is used.
    var jwsCompact = jws.CreateJws();
    if (jws.LastMethodSuccess == false) {
        console.log(jws.LastErrorText);
        return;
    }

    console.log("JWS: " + jwsCompact);

    // Note: ECC signatures use random values, so the output will be different each time a signature is produced.
    // sample output:
    // JWS: eyJhbGciOiJFUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.J6EGTNkeuEjehHHBu0SOKzifm8r35wbx49A5964pxzB7gannyZZPMkK7vmlaPJ-K8Xmm8cZsQySAPC12Xd8avw

    // Now load the JWS, validate, and recover the original text.
    var jws2 = new chilkat.Jws();

    // Load the JWS.
    success = jws2.LoadJws(jwsCompact);

    var eccPubKey = new chilkat.PublicKey();
    eccKey.ToPublicKey(eccPubKey);

    // Set the ECC public key used for validation.
    signatureIndex = 0;
    jws2.SetPublicKey(signatureIndex,eccPubKey);

    // Validate the 1st (and only) signature at index 0..
    var v = jws2.Validate(signatureIndex);
    if (v < 0) {
        // Perhaps Chilkat was not unlocked or the trial expired..
        console.log("Method call failed for some other reason.");
        console.log(jws2.LastErrorText);
        return;
    }

    if (v == 0) {
        console.log("Invalid signature.  The ECC key was incorrect, the JWS was invalid, or both.");
        return;
    }

    // If we get here, the signature was validated..
    console.log("Signature validated.");

    // Recover the original content:
    console.log(jws2.GetPayload("utf-8"));

    // Examine the protected header:
    var joseHeader = new chilkat.JsonObject();
    jws2.GetProtectedH(signatureIndex,joseHeader);
    joseHeader.EmitCompact = false;

    console.log("Protected (JOSE) header:");
    console.log(joseHeader.Emit());

    // Output:

    // Signature validated.
    // In our village, folks say God crumbles up the old moon into stars.
    // Protected (JOSE) header:
    // { 
    //   "alg": "ES256"
    // }

}

chilkatExample();