Java

Export a Public Key as a JWK

Demonstrates the Chilkat PublicKey.GetJwk method, which returns the public key as a compact JWK (JSON Web Key). It takes no arguments; binary values use Base64url without padding and the member order is stable across calls.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: JWK is the JSON key format used across modern web security — JWT, OAuth, OpenID Connect. Exporting a public key to JWK is exactly what you do to publish it in a JWK Set (a jwks_uri endpoint) so others can verify your signatures. The stable member order matters because it makes the output reproducible, which is important when the JWK feeds into a thumbprint.

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Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
    //  JWK, and other supported representations.
    CkPublicKey pubKey = new CkPublicKey();
    success = pubKey.LoadFromFile("qa_data/public.pem");
    if (success == false) {
        System.out.println(pubKey.lastErrorText());
        return;
        }

    //  Export the public key as a compact JWK (JSON Web Key).  Binary values use Base64url without
    //  padding, and the member order is stable across calls.
    String jwk = pubKey.getJwk();
    if (pubKey.get_LastMethodSuccess() == false) {
        System.out.println(pubKey.lastErrorText());
        return;
        }

    System.out.println(jwk);
  }
}