Java Requires Chilkat v11.0.0+

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 Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.Jws;
import com.chilkatsoft.chilkat2.PrivateKey;
import com.chilkatsoft.chilkat2.PublicKey;
import com.chilkatsoft.chilkat2.StringBuilder;

public class ChilkatExample {

    public static void main(String[] args) {
        // This requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        // Use the following ECC key loaded from JWK format.
        StringBuilder sbJwk = new 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("}");

        PrivateKey eccKey = new 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..)
        try {
            eccKey.loadJwk(sbJwk.getAsString());
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

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

        Jws jws = new Jws();

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

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

        // Set the payload.
        boolean bIncludeBom = false;
        String 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.
        String jwsCompact;
        try {
            jwsCompact = jws.createJws();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("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.
        Jws jws2 = new Jws();

        // Load the JWS.
        jws2.loadJws(jwsCompact);

        PublicKey eccPubKey = new 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..
        int v = jws2.validate(signatureIndex);
        if (v < 0) {
            // Perhaps Chilkat was not unlocked or the trial expired..
            System.out.println("Method call failed for some other reason.");
            System.out.println(jws2.getLastErrorText());
            return;
        }

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

        // If we get here, the signature was validated..
        System.out.println("Signature validated.");

        // Recover the original content:
        System.out.println(jws2.getPayload("utf-8"));

        // Examine the protected header:
        JsonObject joseHeader = new JsonObject();
        jws2.getProtectedH(signatureIndex, joseHeader);
        joseHeader.setEmitCompact(false);

        System.out.println("Protected (JOSE) header:");
        System.out.println(joseHeader.emit());

        // Output:

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