Java Requires Chilkat v11.0.0+

Validate a JWS Using ECDSA P-521 SHA-512

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) that uses ECDSA P-521 SHA-512 Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.Jws;
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.

        // This example takes a JSON signature in compact serialization format,
        // and uses an ECDSA public key to validate and recover the protected header and payload.

        // We only need a public key for signature validation.  This is the ECDSA public key
        // that is used:

        //      {"kty":"EC",
        //       "crv":"P-521",
        //       "x":"AekpBQ8ST8a8VcfVOTNl353vSrDCLLJXmPk06wTjxrrjcBpXp5EOnYG_NjFZ6OvLFV1jSfS9tsz4qUxcWceqwQGk",
        //       "y":"ADSmRA43Z1DSNx_RvcLI87cdL07l6jQyyBXMoxVg_l2Th-x3S1WDhjDly79ajL4Kkd0AZMaZmh9ubmf63e3kyMj2"
        //      }

        StringBuilder sbPubKey = new StringBuilder();
        sbPubKey.append("{\"kty\":\"EC\",");
        sbPubKey.append("\"crv\":\"P-521\",");
        sbPubKey.append("\"x\":\"AekpBQ8ST8a8VcfVOTNl353vSrDCLLJXmPk06wTjxrrjcBpXp5EOnYG_NjFZ6OvLFV1jSfS9tsz4qUxcWceqwQGk\",");
        sbPubKey.append("\"y\":\"ADSmRA43Z1DSNx_RvcLI87cdL07l6jQyyBXMoxVg_l2Th-x3S1WDhjDly79ajL4Kkd0AZMaZmh9ubmf63e3kyMj2\"");
        sbPubKey.append("}");

        PublicKey pubKey = new PublicKey();
        try {
            pubKey.loadFromString(sbPubKey.getAsString());
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        Jws jws = new Jws();

        // Set the ECC public key:
        int signatureIndex = 0;
        jws.setPublicKey(signatureIndex, pubKey);

        // Load the JWS.
        StringBuilder sbJws = new StringBuilder();
        sbJws.append("eyJhbGciOiJFUzUxMiJ9");
        sbJws.append(".");
        sbJws.append("UGF5bG9hZA");
        sbJws.append(".");
        sbJws.append("AdwMgeerwtHoh-l192l60hp9wAHZFVJbLfD_UxMi70cwnZOYaRI1bKPWROc-mZZq");
        sbJws.append("wqT2SI-KGDKB34XO0aw_7XdtAG8GaSwFKdCAPZgoXD2YBJZCPEX3xKpRwcdOO8Kp");
        sbJws.append("EHwJjyqOgzDO7iKvU8vcnwNrmxYbSW9ERBXukOXolLzeO_Jn");

        try {
            jws.loadJwsSb(sbJws);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Validate the 1st (and only) signature at index 0..
        int v = jws.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(jws.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.");
        System.out.println("--");

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

        // Examine the protected header:

        JsonObject joseHeader = new JsonObject();
        try {
            jws.getProtectedH(signatureIndex, joseHeader);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        joseHeader.setEmitCompact(false);

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

        // Output:
        // (the string "Payload" was the content that was signed.)

        //     Signature validated.
        //     --
        //     Recovered content:
        //     Payload
        //     --
        //     Protected (JOSE) header:
        //     {
        //       "alg": "ES512"
        //     }
    }
}